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1.
OBJECTIVE: To delineate the cytomorphologic features seen in cancer of the breast during pregnancy and lactation, to compare them to the cytomorphologic parameters in benign conditions and to determine the feasibility of differentiating features of malignant breast carcinoma from those of benign breast lesions during pregnancy. STUDY DESIGN: The study group consisted of pregnant or lactating women with breast carcinoma and with benign breast lesions who underwent fine needle aspiration (FNA) of the breast lesions. The findings of FNA were reviewed, analyzed, tabulated and correlated with the pathologic diagnosis of the breast biopsies. RESULTS: Eleven patients had malignant cytomorphologic changes, including increased cellularity, multilayering, enlarged and pleomorphic nuclei, single or multiple nucleoli, mitosis and numerous isolated tumor cells. Secretory changes were scanty. The background was foamy and necrotic. FNA of the benign lesions showed a biphasic cell pattern with cohesion; minimal nuclear pleomorphism; single, regular nucleoli; and naked nuclei in a granular background with foamy macrophages. Increased cellularity with nuclear atypia, single cells and a dirty background was seen in benign and malignant conditions. CONCLUSION: The main cytologic features that differentiate breast carcinoma from benign conditions during pregnancy and lactation are crowding and overlapping of nuclei, dyscohesion and enlarged, pleomorphic nuclei with irregular nuclear membranes, coarse nuclear chromatin and mitoses. Pregnancy-related hyperplastic changes with atypia can potentially result in a false positive diagnosis of carcinoma.  相似文献   

2.
OBJECTIVE: The clinical, mammographic and low grade cytologic features of mucinous carcinoma can make it difficult to diagnose by fine needle aspiration (FNA). Fine needle aspirates of mucinous carcinoma were reviewed with the mammographic findings to improve the diagnostic criteria and specificity for FNA. STUDY DESIGN: All aspirates were reviewed for cytologic criteria and cellularity, atypia and single epithelial cells (SEC). A nuclear grade was assigned to each aspirate. The mammographic findings were correlated with the FNA diagnoses. RESULTS: Forty-five patients with an aspirate and confirmed diagnosis of mucinous carcinoma were identified. The clinical impressions were: benign tissue (5), fibroadenoma (6) and cancer (32). The initial cytologic diagnoses were: adenocarcinoma (32), atypical/suspicious for cancer (11), insufficient (1) and negative (1). The cytologic findings showed smears with increased cellularity (35/45 cases) and minimal atypia. SEC with eccentrically located nuclei and eosinophilic cytoplasm were numerous. The assigned nuclear grade was as follows: grade 1, 16 cases; grade 2, 20 cases; and grade 3, 6 cases. Abundant mucin was present in Papanicolaou-stained slides in 23 cases; focal mucin was observed in 14 cases. The mammograms showed a smoothly outlined to lobulated mass with only slight irregularities identified. CONCLUSION: Mucinous carcinoma has a cytologic pattern that includes increased cellularity, with numerous single cells and abundant mucin. Although the mammographic findings may mimic a benign lesion, in the most patients a specific diagnosis of mucinous carcinoma can be made by FNA.  相似文献   

3.
BACKGROUND: It is often difficult to determine whether a mass in the pancreas is benign or malignant. The goal was to evaluate whether endoscopic ultrasound (EUS) can reliably establish whether a mass is benign or malignant. METHODS: One hundred five patients with possible pancreatic tumors were referred for EUS. Those who were found to have a lesion suspicious for carcinoma and did not have a known malignancy also underwent EUS-guided FNA. RESULTS: A mass suspicious for cancer was identified in 73 patients, whereas inflammatory changes or a normal pancreas was noted in 32 patients. Four of the latter 32 patients were subsequently found to have cancer. EUS-guided FNA was performed on 47 of the 73 patients with a suspicious mass and was read as cancer in 27 patients, atypia in 10 patients, and benign in 10 patients. All 10 patients with atypia were subsequently confirmed to have cancer, and 6 of the 10 patients with a benign FNA were proved to have a tumor at surgery. EUS could differentiate the lesion as malignant with a sensitivity of 95%, specificity 88%, positive predictive value 95%, and negative predictive value 88%. CONCLUSIONS: Radial array EUS is helpful in supporting or refuting a diagnosis of cancer in a patient with a pancreatic mass. Although EUS-guided FNA can confirm the diagnosis, a negative FNA should not preclude exploration when clinically indicated.  相似文献   

4.
OBJECTIVE: To characterize the cytomorphologic features of pilomatrixoma. STUDY DESIGN: Aspirate findings in nine cases of PMX were correlated with clinical data and subsequent histology. This relatively large volume of case material afforded an opportunity to test the cytologic criteria that have been proposed as diagnostic of pilomatrixoma in the case reports published previously. RESULTS: Ghost cells, basaloid cells and calcium deposits were the features found to be most characteristic of PMX and were observed in all four cases in which a correct diagnosis was made originally. CONCLUSION: The presence of ghost cells seems to be the key to recognizing PMX. These cells are visible in the majority of air-dried smears but seldom in alcohol-fixed smears. Adequate cytologic sampling and the routine use of both wet-fixed and air-dried smears should preclude an incorrect diagnosis.  相似文献   

5.
Pilomatrixoma is an uncommon benign tumor arising from hair follicles. They occur most commonly in the head and neck region, and are usually found in girls during the first two decades of life. These tumors may contain calcification, which, when present, is helpful in suggesting the diagnosis. We present a classic case of pilomatrixoma in the cheek of a young woman. The tumor was documented on CT studies, which showed a subcutaneous, noninvasive mass with calcifications.  相似文献   

6.
OBJECTIVE: To determine the contribution of percutaneous cutting needle biopsy (PNB) subsequent to fine-needle aspiration (FNA) in the diagnosis of chest lesions. DESIGN: A retrospective review of 220 patients who underwent CT-guided FNA followed immediately by PNB performed at our center between 1988 and 1995 was undertaken. Thirty-eight patients were excluded because FNA and/or PNB specimens were nondiagnostic, yielding a study group of 182 patients. RESULTS: A diagnosis of malignancy was made in 141 (77.5%) and nonmalignancy in 41 (22.5%) cases. The yield of histospecific diagnosis due to FNA was marginally higher than PNB in malignant lesions (86.5% vs 78%, respectively). In contrast, PNB was superior to FNA for the histospecific diagnosis of benign lesions (87.8% for PNB vs 31.7% for FNA, p<0.00001) and lymphomas (88% for PNB vs 56% for FNA, p<0.05). In 58.8% of the patients with benign lesions and in 37.5% of the patients with lymphoma, PNB performances altered clinical management, either by avoiding further surgery or allowing specific medical treatment. Pneumothorax occurred in 24.7% of the cases but only five patients (2.7%) required hospitalization. CONCLUSION: PNB is extremely effective for making a specific diagnosis in benign lesions compared with FNA. PNB does not increase the yield of histospecific diagnosis for malignant lesions except for the subset of lymphoma, where it seems to provide important additional information in many instances. We recommend that FNA be performed as the initial procedure, followed by PNB in cases of equivocal diagnosis of carcinoma, for lymphoma and for suspected benign lesions.  相似文献   

7.
ThinPrep processing, an automated cytopreparatory method, has been reported to show good correlation with conventional preparations and to reduce the rate of false-negative diagnoses. In a retrospective review of 230 consecutive nongynecologic cytology cases, we compare the ThinPrep (TP) method with conventional preparations (CP). There were 129 fine-needle aspiration (FNA) specimens from various sites, including 51 breasts, 40 thyroids, 14 lungs, 8 livers, and 16 miscellaneous sites. The sources of 101 body cavity fluids included 68 pleural/peritoneal effusions, 25 peritoneal/pelvic washings, and 8 miscellaneous sites. Each case was evaluated for cellularity, morphologic, details, and obscuring background material. Diagnoses of the TP slides were classified as insufficient, normal, benign, suspicious, or malignant. Each case was then correlated with the tissue diagnosis when available. In TP slides, cellular arrangements, nuclear details, and nuclear cytoplasmic ratio were preserved, while blood and diathesis were eliminated. There was no statistically significant difference between TP and CP in the diagnostic categories. However, in six cases of "insufficient for diagnosis" on FNA by CP, TP yielded sufficient cells and tissue fragments for diagnosis. One case each of FNA and body fluid with a diagnosis of "suspicious for malignancy" by CP was considered "positive" on TP slides. The overall sensitivity of TP was 97.6%, and the specificity was 92.9%. The positive predictive value was 93.0%. We conclude that the ThinPrep method shows good correlation with conventional preparations in both FNA and body fluids.  相似文献   

8.
BACKGROUND: Ectopic cervical thymoma, first described in 1941 by Boman, is an uncommon tumor of the neck displaying the same histologic features as mediastinal thymoma. Since it is commonly located in the anterolateral part of the neck or is subjacent to or inside the lower pole of the thyroid, the mass is often confused as being of thyroid origin. CASE: A 68-year-old female presented with dyspnea and an anterior neck mass found on routine chest roentgenography. The thyroid scan showed a cold nodule in the lower pole of the left part of the thyroid. Fine needle aspiration (FNA) cytology revealed large numbers of small lymphocytes with hyperchromatic nuclei and frequent clumping pattern in the pale, eosinophilic, fluid background. A few clusters of epithelial cells without atypism were interpreted as thyroid follicular cells. The overall cytologic features were misinterpreted as malignant lymphoma of the thyroid. However, the histologic diagnosis was thymoma, predominantly cortical type. CONCLUSION: The ectopic cervical thymoma is sometimes misdiagnosed as Hashimoto's thyroiditis, anaplastic carcinoma and malignant lymphoma of thyroid on FNA cytology or frozen diagnosis due to its rarity. Therefore, the differential diagnosis of a neck mass showing a variable composition of lymphocyte and epithelial component in a pale, eosinophilic, fluid background should also include ectopic cervical thymoma, especially in elderly females.  相似文献   

9.
OBJECTIVE: To present our experience with liver fine needle aspiration (FNA) diagnosis based on Riu's stain. STUDY DESIGN: We reviewed a total of 322 liver fine needle aspirates from 286 patients seen in a seven-year period from April 1990 to April 1997 at Koo Foundation Sun Yat-Sen Cancer Center, Taipei. Surgical and/or clinical follow-up was available for confirmation in 292 aspirates. RESULTS: The cytologic diagnosis was categorized into four groups: benign in 81 cases, suspicious in 13, malignant in 225, and inadequate specimen in 3 cases. There were 16 false negative and no false positive diagnoses. Two suspicious aspirates were negative. Our results showed a sensitivity of 93.3% and a specificity of 100% for the detection of malignancy. If suspicious cases were considered positive, the specificity decreased to 95.1%, while the sensitivity increased to 93.6%. Among 87 hepatocellular carcinomas (HCCs) in our series, correct FNA diagnosis was made in 84 cases with an accuracy of 96.6%. Out of 135 cases of non-HCCs, 1 was incorrectly diagnosed. The accuracy of identifying a liver malignancy as non-HCC was 99.3%. CONCLUSION: Cytologic features of HCC are well demonstrated by Riu's stain, with high accuracy in identifying them. Liver FNAs using Riu's stain combined with cell block study and clinicopathologic correlation can achieve very high sensitivity and specificity in the detection of hepatic malignancies.  相似文献   

10.
OBJECTIVE: The aim of this study was to evaluate the effectiveness of fine-needle aspiration (FNA) in the diagnosis of primary lymphoid processes of the salivary gland. DESIGN: A retrospective study. METHOD: Between 1987 and 1994, 35 patients who underwent fine-needle aspiration (FNA) of the salivary gland had a diagnosis of a primary lymphoid process. Most presented with palpable parotid (28 patients) or submandibular (4 patients) gland masses which prompted a clinical diagnosis of pleomorphic adenoma. FNA was performed with immediate on-site evaluation. Flow cytometric cell-surface-marker analysis was performed in 28 of the 35 cases to determine the clonality of the B-cell proliferations. RESULTS: Sixteen cases of reactive hyperplasia and nine cases of malignant lymphoma diagnosed by FNA were confirmed by subsequent histopathologic examination. Lymphoma was confirmed in six of eight cases diagnosed as suspicious for lymphoma by FNA. Hodgkin's disease was suspected but not confirmed in one case and was diagnosed as a probable Warthin's tumour in another case. In all cases, the FNA diagnosis of either a reactive or malignant lymphoid process was unexpected and influenced the patient's further management. For patients diagnosed with an intraparotid lymph node, surgery could be deferred for a short period with the hope that the lymphadenopathy would spontaneously regress. For patients with a preoperative FNA diagnosis of lymphoma, a more limited biopsy could be performed, thereby reducing the operative risk to the patient and plans to process the tissue according to the institution's lymphoma protocol could be made. CONCLUSION: Clinically, reactive intraparotid lymph nodes and lymphomas present as parotid enlargements that are indistinguishable from pleomorphic adenomas. FNA is the only method of accurately establishing a preoperative diagnosis in these patients.  相似文献   

11.
BACKGROUND: Giant cell tumor of tendon sheath (GCTTS), also known as localized nodular tenosynovitis, is a benign neoplasm that occurs principally on the digits. The cytomorphologic features of this lesion on fine needle aspiration (FNA) have not been fully characterized. CASES: In case 1, a 23-year-old female presented with a circumscribed soft tissue swelling in the left second toe. In case 2, a 16-year-old female presented with a tender swelling at the base of the right great toe. FNA smears in both instances were highly cellular, with mononuclear cells predominating and interspersed binucleated and multinucleated osteoclastlike giant cells along with hemosiderin-laden macrophages. CONCLUSION: When interpreted along with clinical data, the diagnosis of GCTTS can usually be made with certainty using FNA cytology.  相似文献   

12.
The cytologic diagnosis of follicular variant of papillary thyroid carcinoma (FVPTC) can be difficult owing to the paucity of nuclear changes of papillary carcinoma and overlapping features with other follicular-derived lesions. We report our fine-needle aspiration (FNA) experience with 17 histologically proved cases of FVPTC with a preceding FNA. All cases showed increased cellularity and a background of moderate to abundant thin watery colloid with variable amounts of thick eosinophilic colloid. The cells were arranged mainly in monolayer sheets and syncytial fragments; occasional microfollicle formation with abundant fine eosinophilic cytoplasm was seen. Nuclear enlargement was a consistent finding in all cases. Only 5 cases showed prominent nuclear features of papillary carcinoma. Histologic examination showed encapsulated follicular-patterned nodules with multifocal random distribution of nuclear features of papillary carcinoma that were more pronounced in the subcapsular locations of the lesions. This morphologic heterogeneity explains the variability seen in FNA specimens of FVPTC and may result in false-negative diagnoses. We believe that these findings should be considered when interpreting follicular lesions; suspicion of an FVPTC should be conveyed in the cytopathology report, which may prompt intraoperative assessment to avoid a second surgical intervention for completion thyroidectomy.  相似文献   

13.
AIMS: To evaluate the correlation of fine needle aspiration (FNA) cytology and frozen section biopsy in the diagnosis of thyroid nodules. METHODS: The medical records of 662 patients who underwent FNA cytology of the thyroid and thyroid surgery were analysed. Frozen section biopsies were taken from 586 of the 662 patients. The diagnostic correlations of FNA cytology, frozen section, and both FNA cytology and frozen section with definitive histological assessment were evaluated. RESULTS: Among the 662 patients who received FNA cytology, there were 356 cases (53.8%) diagnosed as benign, 114 cases (17.2%) as malignant, 148 cases (22.4%) as indeterminate, and 44 cases (6.6%) as unsatisfactory. The positive predictive value for the detection of malignancy by FNA cytology was 92.1% and the negative predictive value was 95.2%. The incidence of malignancy in the indeterminate cytological diagnosis was 23%. The diagnosis from frozen sections was benign in 445 cases (75.9%), malignant in 134 cases (22.9%), and deferred in 7 cases (1.2%). By frozen section, the positive and negative predictive values were 97% and 95.5%, respectively. Diagnostic accuracy up to 98% was achieved when FNA cytology and frozen section diagnoses were in agreement. No false positives were observed when FNA cytology and frozen sections were both positive for malignancy. When FNA cytology and frozen section diagnoses were discordant, frozen section showed a higher accuracy (78.9%) than FNA cytology (21.1%). In the face of an indeterminate or unsatisfactory cytological diagnosis, the diagnostic accuracy of frozen sections reached 92.6%. CONCLUSIONS: The results confirm that FNA cytology is a useful tool in the initial evaluation of thyroid nodules. Intraoperative frozen section is a valuable procedure to confirm the cytological diagnosis and identify malignancy in patients with indeterminate or unsatisfactory cytological diagnosis. With reliance on frozen sections as an intraoperative guide of thyroid surgery, the possibility of unnecessary extensive surgery and the need for the second operation are considerably lower.  相似文献   

14.
OBJECTIVE: To compare, contrast and analyze the value and limitations of fine needle aspiration (FNA) cytology and core biopsy (CB) in a rural setting. STUDY DESIGN: Retrospective analysis of 100 FNA cytology and 100 CB results of mass lesions from 193 patients matched for age, sex and body organs, and referred for FNA or CB in rural New South Wales, Australia, between September 1990 and May 1996. RESULTS: FNA cytology and CB results from 193 patients were analyzed, based on anatomic location and cytologic criteria. Sites included lung, retroperitoneum, liver, breast, kidney, pancreas and ovary. The FNA group contained 6 inadequate, 14 benign, 3 atypical, 6 suspicious and 71 malignant cases, whereas the CB group had 1 inadequate, 24 benign and 75 malignant conditions. The inadequate samples in both groups were due to technical difficulty in obtaining representative material. The indeterminate (atypical and suspicious) group, which was the main pitfall of FNA, contained 4 low grade carcinomas, 3 low grade non-Hodgkin's lymphomas and 2 fibrocystic breast changes. The benign FNA group comprised 8 cysts, 5 inflammatory/reactive conditions and 1 benign tumor/hamartoma, whereas the benign CB group contained 11 cysts, 9 inflammatory/reactive conditions and 4 benign tumors. CONCLUSION: FNA was comparable to CB at most anatomic sites. CB occasionally offered additional information. This slight advantage was due to the availability of tissue from the first and often the only pass for assessment of architecture and performance of ancillary tests, which obviated the need for further sampling. On-site assessment of the core imprints at the time of the procedure by the highly skilled and experienced interventional cytopathologist was responsible for limiting the number of attempts to one core in most of the instances, therefore minimizing complications. Pathologists are encouraged to become more familiar with the criteria of aspiration cytology, which has proven its validity in the new cost-conscious environment. Despite the recent surge in the popularity of core biopsy, FNA cytology, when practiced in a multidisciplinary setting, with involvement of pathologists, radiologists and clinicians, is an extremely accurate test with very high sensitivity, which approaches that of surgical pathology, and specificity very similar to that of frozen section. FNA has a positive predictive value for a malignant diagnosis of almost 100%. FNA is a well-tolerated, relatively noninvasive test with a very low risk of complications.  相似文献   

15.
This article describes the use of computer-based analytical techniques to define nuclear size, shape, and texture features. These features are then used to distinguish between benign and malignant breast cytology. The benign and malignant cell samples used in this study were obtained by fine needle aspiration (FNA) from a consecutive series of 569 patients: 212 with cancer and 357 with fibrocystic breast masses. Regions of FNA preparations to be analyzed were converted by a video camera to computer files that were displayed on a computer monitor. Nuclei to be analyzed were roughly outlined by an operator using a mouse. Next, the computer generated a "snake" that precisely enclosed each designated nucleus. The computer calculated 10 features for each nucleus. The ability to correctly classify samples as benign or malignant on the basis of these features was determined by inductive machine learning and logistic regression. Cross-validation was used to test the validity of the predicted diagnosis. The logistic regression cross validated classification accuracy was 96.2% and the inductive machine learning cross-validated classification accuracy was 97.5%. Our computerized system provides a probability that a sample is malignant. Should this probability fall between 30% and 70%, the sample is considered "suspicious," in the same way a visually graded FNA may be termed suspicious. All of the 128 consecutive cases obtained since the introduction of this system were correctly diagnosed, but nine benign aspirates fell into the suspicious category.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

16.
OBJECTIVE: To study the role of liver fine needle aspiration (FNA) in the diagnosis of kala-azar with an atypical presentation. STUDY DESIGN: The study group consisted of 23 patients (aged 18-37). All were admitted to Shiraz University Hospitals for the investigation of fever of unknown origin. The immunofluorescent antibody titer for kala-azar was positive (> 1:256 dilution). However, routine abdominal sonography revealed multiple small, hypoechoic lesions in the liver, more suggestive of metastatic tumor or miliary tuberculosis. The lesions were aspirated for cytologic diagnosis. RESULTS: The smears revealed many atypical hepatocytes, groups of epithelioid histiocytes and, in 15 patients, macrophages containing few to many Leishman bodies, allowing a diagnosis of kala-azar. The liver needle biopsy specimens confirmed the cytologic diagnosis of kala-azar and liver cell atypia. The patients were given glucantime therapy, and 21 recovered; 1 patient was lost to follow-up, and 1 died during treatment. CONCLUSION: Liver FNA is a useful procedure for the diagnosis of kala-azar, particularly in cases with atypical clinical presentations.  相似文献   

17.
OBJECTIVE: To investigate whether testicular cytology may be considered diagnostic in the evaluation of infertile men. PATIENTS AND METHODS: Specimens of testicular tissue obtained either surgically (imprint smear) or through fine-needle aspiration (FNA) were used as a source of cytological smears; 58 testes from 24 men with azoospermia or severe oligospermia and from five men with advanced prostate cancer were evaluated cytologically and compared with the histological diagnosis. RESULTS: FNA caused no apparent trauma. The results from FNA smears generally agreed with the histological findings but four patients with no spermatozoa in the FNA smears were diagnosed histologically as hypospermatogenic and two others judged histologically as having Sertoli-cell-only (SCO) syndrome and spermatogenic arrest had detectable spermatozoa in their FNA smears. There was complete agreement between the results of imprint smears and histological findings in those patients with SCO syndrome and spermatogenic arrest. There were no evident differences in sperm counts between hypospermatogenesis and normal spermatogenesis on the imprint slides, but FNA smears detected this difference. CONCLUSION: FNA of the testis is a relatively non-invasive and reproducible technique for evaluating qualitative and quantitative cytology. However, it is insufficient for diagnosing some testicular pathologies. Imprint smears supplement the histological diagnosis, especially if the histological slides are stained unsatisfactorily.  相似文献   

18.
AIM: To review fine needle aspiration (FNA) cytology from sites other than the breast a year before and a year after the introduction of a near patient FNA diagnosis (NPFD) service in which the FNA were performed by a pathologist and reported within a few minutes. METHODS: The setting was a large hospital in rural New Zealand. The year before the introduction of the NPFD service was examined retrospectively, and the year after prospectively. The pattern of use and the quality of the results before and after starting the NPFD service were compared. RESULTS: Time taken to report the specimens decreased from a few days to a few minutes. There were statistically significant changes in the following: an increase from 237 to 304 in the number of non-breast FNA performed, and in particular an increase from 65 to 113 in the number for general surgery; an increase in the use of immunolabelled flow cytometry from 0 to 19 and cell blocks from 3 to 41; an increase in specificity from 53% to 80%; a decrease in the overall inadequacy rate from 29% to 9%; and a decrease in the inadequacy rate for cancers from 9% to 2%. The cost of the non-breast FNA service increased by about 9200 Pounds a year. CONCLUSIONS: Starting an NPFD service for sites other than the breast greatly reduced the reporting time and produced statistically significant increases in the use of FNA cytology and in the quality of the results.  相似文献   

19.
OBJECTIVE: To describe the diagnostic cytologic features of low grade papillary adenocarcinomas of minor salivary gland origin (LPA) along with its pertinent differential diagnostic entities. STUDY DESIGN: The study was based on a histologically confirmed case of LPA that recurred after multiple excisions. Fine needle aspiration (FNA) was performed during the most recent recurrence. RESULTS: Low-power examination showed geographic sheets and papillary groups of epithelial cells. Individual cells were medium sized, with scant cytoplasm, finely clumped chromatin and occasional prominent nucleoli. Pleomorphism was conspicuously absent. Differential diagnosis included cellular mixed tumor, basal cell adenoma, basal cell adenocarcinoma, low grade mucoepidermoid carcinoma and metastatic papillary carcinoma. CONCLUSION: LPA can be accurately diagnosed by FNA biopsy. However, the cytopathologist must entertain and exclude various differential diagnostic entities.  相似文献   

20.
Pilomatrixoma is a benign tumour of the cutaneous adnexa. Histologically, pilomatrixoma comprises masses of immature basophilic cells, small numbers of polygonal squamoid cells, few transitional cells, and clusters of 'shadow cells'. The mechanism leading to the formation of shadow cells is still unknown. Skin biopsy specimens of pilomatrixoma (n = 15) were studied histologically, immunohistologically, and by applying the in situ end-labelling technique. The basal layer of the basophilic cells induced most of the proliferating cells with high expression of bcl-2 and cytokeratin 19. The overlying basophilic cells showed a negligible mitotic activity, a high significant accumulation of p53 protein, and a heterogeneous, but progressive loss of bcl-2 and cytokeratin 19. They developed either into squamoid cells or into transitional cells. The squamoid cells were characterized as differentiated cells resembling mature keratinocytes of stratified mucosa. The transitional cells could be shown to represent apoptotic cells proceeding to shadow cells. The data suggest that apoptosis is the main mechanism leading to the development of the dead shadow cells and is most probably responsible for the banal biological behaviour of pilomatrixoma. Apart from that, pilomatrixoma represents a suitable biological model to study apoptosis in humans.  相似文献   

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