Ultrasound guided percutaneous fine needle aspiration cytology of pancreas: a review of 61 cases

The study includes 61 cases which were subjected to ultrasound (US) guided fine needle aspiration cytology (FNAC) to find out the utility of this technique in the diagnosis of pancreatic lesions. Age of the patients ranged from 23 to 85 years with a median of 50 years. Male to female ratio was 36:25. One or more clinical diagnoses were offered in 16 and in 9 of these, the disease was related to pancreas. Subsequent to US, the lesions were localized to pancreas in 57 and the nature of pathology in the pancreatic lesion could be diagnosed in 31. By FNAC, 31 cases (50.8%) were diagnosed to have pancreatic malignancy which included adenocarcinoma (23 cases), papillary cystic tumour (1), muco-epidermoid carcinoma (1), acinic cell carcinoma (1), islet cell tumor (1), and non Hodgkin lymphoma (4). FNAC of liver in 2 cases and retroperitoneal lymph node in a case of pancreatic adenocarcinoma revealed metastasis. During follow up, 1 case of non Hodgkin's lymphoma showed CSF involvement. Three cases (4.9%) were suspected to have epithelial malignancy of which one was confirmed as an adenocarcinoma following surgery and histology. Four (6.6%) were benign lesions which included nonspecific inflammation (2 cases), tuberculous pancreatitis (1) and pseudopancreatic cyst (1). The remaining 23 cases (37.7%) had normal or inadequate cytology. Of these, FNAC of liver showed metastasis in 2 cases and one case each were diagnosed as adenocarcinoma and pseudopancreatic cyst respectively following surgery. None of the patients had any complication following FNAC. We recommend US guided FNAC to be routinely used for diagnosis of pancreatic lesion.     

Ultrasound guided fine needle aspiration cytology in abdominal tuberculosis

Although barium studies and CT are useful in assessing abdominal pathology in tuberculosis, imaging findings are not always specific and a histopathological or bacteriological confirmation is often required. The aim of the present study was to evaluate the role of ultrasound (US) guided fine needle aspiration cytology (FNAC) in the diagnosis of abdominal tuberculosis in patients with non-palpable lesions detected on US/CT. FNAC was performed on 31 sites in 30 patients. The sites included enlarged lymph nodes (n = 14), focal lesions in liver (n = 2) and spleen (n = 8), and thickened bowel in the ileocaecal region (n = 7). The results were classified cytomorphologically into four groups: (1) definite evidence of tuberculosis; (2) presumptive evidence of tuberculosis; (3) suggestive of tuberculosis; and (4) negative for tuberculosis. 18 of the 31 FNACs (58%) revealed a positive diagnosis of tuberculosis (definite evidence in nine patients and presumptive evidence in nine patients). 13 of the 31 FNACs (42%) showed either necrosis alone (n = 4) or negative results (n = 9). Zeihl-Neelson staining for acid-fast bacilli on direct smear was positive in only nine patients (29%). Splenic and lymph nodal FNAC had a high sensitivity (87.5% and 78.6%, respectively) in the diagnosis of tuberculosis. None of the bowel and liver FNACs was diagnostic. No complications were encountered. US guided FNAC offers a safe and accurate method of achieving a diagnosis in patients with suspected abdominal tuberculosis who present with radiologically demonstrable but non-palpable lesions, especially those involving lymph nodes and spleen.     

Stromal fragments in invasive carcinoma. Source of diagnostic difficulty in aspiration cytology

OBJECTIVE: To analyze three cases of stromal fragments in invasive carcinoma that created diagnostic difficulty in aspiration cytology. STUDY DESIGN: A retrospective review of fine needle aspiration cytology (FNAC) smears of a breast tumor, scalp tumor and neck mass. Cytomorphologic features of all the smears were reviewed after histology became available. RESULTS: FNAC smears revealed a biphasic pattern: a carcinomatous component and a stromal component that was either discrete or in close apposition to the carcinoma. The cytopathologist had suggested the diagnosis of a biphasic tumor in each case--phyllodes, malignant skin adnexal and salivary gland tumor. Histopathology revealed an invasive carcinoma with altered stroma in the first two cases and metastatic lymph node with perinodal soft tissue extension in the third case. CONCLUSION: Stromal changes in response to infiltrating carcinoma are well documented in surgical pathology. However, these may also be encountered in FNAC smears. The above cases stress the importance of recognizing stromal fragments in aspiration cytology in order to avoid diagnostic errors.     

FNAC guided by computed tomography in the diagnosis of primary pancreatic adenosquamous carcinoma. A report of three cases

BACKGROUND: Pancreatic adenosquamous carcinoma (ASqC) is an unusual histologic subtype of nonendocrine neoplasia of the pancreas. Although fine needle aspiration cytology (FNAC) is now accepted as a reliable procedure for the diagnosis of pancreatic malignancies, many of these unusual tumors are still diagnosed after surgery or at necropsy. CASES: Between January 1995 and July 1996, 3 of 35 primary pancreatic malignant tumors were diagnosed as ASqC based on computed tomography-guided FNAC. After cytologic diagnosis, all three patients were treated with neoadjuvant chemotherapy and radiotherapy. Two patients completed the treatment and underwent a surgical pancreatic-duodenectomy with antrectomy. The remaining patient is currently under treatment. That patient had a highly infiltrative pancreatic mass that affected the muscular small bowel wall. An endoscopic biopsy was performed. The cytologic diagnosis was confirmed by histology in all cases. Immunohistochemically both components, squamous and glandular, showed reactivity for several keratins, while only the glandular pattern was reactive with carcinoembryonic antigen (CEA). CONCLUSION: FNAC is an accurate, rapid and sensitive tool in the diagnosis of ASqC of the pancreas. We recommend a careful search for both malignant components. Immunoreactivity for CEA can be of help in the detection of the glandular component of this tumor.     

Diagnosis of occult thyroid carcinoma by thyroid ultrasonography with fine needle aspiration cytology

OBJECTIVE: To assess the role of ultrasonography and fine needle aspiration cytology (FNAC) in preoperative diagnosis of patients with occult thyroid carcinoma (OTC). STUDY DESIGN: Data on 768 thyroid carcinoma patients receiving primary treatment at Chang Gung Medical Center were retrospectively reviewed. Of these patients, 97 had OTC. To detect small thyroid nodules early and define the characteristics of clinically palpable nodules, thyroid ultrasonography with FNAC were performed on 67 histopathologically proven OTC patients. Analysis for diagnostic value was done for ultrasonography and FNAC. RESULTS: In the 67 patients receiving ultrasonography with FNAC, 23 were preoperatively diagnosed as having papillary thyroid carcinoma and 1 as having follicular carcinoma. The tumor size of these 24 preoperative FNAC-proven OTC was 0.81 +/- 0.23 cm (mean +/- SD). In the remaining patients, 10 presented pictures suspicious for malignancy, with a mean tumor size 0.63 +/- 0.24 cm, and 33 (49.3%) were diagnosed as having benign thyroid lesions in preoperative FNAC. The tumor size in these 33 lesions was 0.58 +/- 0.24 cm. Fifty-seven of the 67 OTC patients received frozen sections. Thirty-eight papillary thyroid carcinomas and four follicular carcinomas were correctly diagnosed on frozen sections. CONCLUSION: Although the rate is not high, high-resolution ultrasonography and FNAC is the best approach to preoperative diagnosis for OTC patients today.     

Fine needle aspiration cytology of tubular carcinoma of the breast

OBJECTIVE: To analyze six cases of tubular carcinoma involving the breast in which the diagnosis was made by fine needle aspiration cytology (FNAC). STUDY DESIGN: All patients were females between the ages of 28 and 67 years. The aspiration findings were confirmed by subsequent cell blocks of the aspirates and tissue examination of the breast mass. The aspirate was obtained using multiple passes in the breast masses while maintaining negative pressure. RESULTS: The cytohistologic features in all cases were characterized by a bland and orderly appearance of cells, few cell atypias, variable numbers of myoepithelial cells, tubular structures and somewhat angular epithelial clusters. The value of immunocytochemical study in the diagnosis was uncertain. CONCLUSION: The uncommon occurrence of tubular carcinoma of the breast, the bland and orderly appearances of cells in FNAC samples (as in tissue) and the difficulties in the cytodiagnosis can be found in other breast conditions. A cautious attitude toward the diagnosis of tubular carcinoma from FNAC samples is necessary, and cell atypias, when seen, should be reported with a recommendation for removal of the breast lump for detailed tissue examination.     

Aberrant tau phosphorylation and neurite retraction during NGF deprivation in PC12 cells

OBJECTIVE: To investigate the final results of cases with preoperative diagnoses of thyroid follicular neoplasms by fine needle aspiration cytology (FNAC). STUDY DESIGN: A retrospective review of 6,499 patients who received thyroid ultrasonography with FNAC at Chang Gung Memorial Hospital. Among 6,499 patients, 209 (3.2%) were diagnosed by FNAC as having follicular neoplasms, of which 84 received surgical treatment. Eighty-two of the 84 cases had a frozen section prepared during the operation. RESULTS: Thyroid malignancy was confirmed histopathologically in 164 cases. Among 84 thyroid follicular neoplasm patients, 21 cases were diagnosed as malignant tumors, including papillary thyroid carcinoma, follicular thyroid carcinoma, medullary thyroid carcinoma and Hürthle's cell carcinoma. Ultrasonography on these 21 patients revealed that 16 cases (76.2%) had low echo density in the thyroid nodule. The percentage was statistically significantly different from that in benign cases, 23.8% (P < .05). A higher incidence of malignancy was found in males, but the data did not reach statistical significance (P = .0586). CONCLUSION: Most of the follicular neoplasms revealed by FNAC were benign lesions. Low echo density on ultrasonography and male sex carried a higher risk of malignancy.     

A lump in the breast. A rare first symptom of ovarian cancer

The breast is an uncommon site for metastasis from extramammary primaries. A 43-year-old woman presented with a lump in the left breast. A tumour with atypical microcalcifications was seen on the mammogram. Needle aspiration cytology revealed adenocarcinoma cells. The final histological diagnosis was papillary adenocarcinoma with psammoma bodies, probably secondary to an ovarian carcinoma. A bilateral carcinoma of the ovaries was subsequently diagnosed and treated. A mammary tumour with an atypical growth pattern and the absence of in situ carcinoma should always prompt the pathologist to considering the possibility of a metastatic tumour even though this is a rare occurrence. Earlier recognition of metastatic tumours to the breast may result in initiation of appropriate therapy and will preclude unnecessary surgical procedures.     

Diagnostic pitfalls of fine needle aspiration cytology for breast disease

We analysed 1500 consecutive fine needle aspiration cytology (FNAC) specimens to ascertain the reasons for diagnostic failure. Of 221 tumours proven malignant following open biopsy, 184 (83%) were correctly diagnosed on FNAC. Of 1082 aspirates classified 'benign', 787 (73%) underwent open biopsy and of these 33 (4%) were diagnosed malignant. All three cases of ductal carcinoma in-situ (DCIS) and eight of 16 lobular carcinomas in this study were missed using FNAC alone. Twelve of the 22 patients with invasive carcinoma not diagnosed on cytology had tumours measuring less than 1 cm diameter. Six of 1500 FNAC reports (0.4%) gave false positive diagnoses, five were classified as 'suspicious of malignancy; and one as 'frankly malignant'. The overall sensitivity was 84%, specificity 99% and positive predictive value 97%. Though these results confirm the value of FNAC as a rapid means of diagnosing most breast cancers, it it unreliable in patients with invasive carcinomas less than 1 cm in diameter and for the detection of lobular and in-situ carcinoma.     

Utility of fine-needle aspiration cytology and frozen-section examination in the operative management of thyroid nodules

Fine-needle aspiration cytology has a high sensitivity for the diagnosis of solitary thyroid nodules. Certain diagnoses involving follicular histologies often cannot be made with needle biopsy alone. The utility of frozen-section examination of thyroid nodules, with particular regard to those lesions with follicular histologies, is also limited. We examined the correlation of fine-needle aspiration cytology and frozen-section examination in solitary thyroid nodules to determine the contribution of frozen-section examination to the operation. We reviewed the fine-needle aspiration cytology, frozen-section examination, and final pathology of 100 consecutive patients undergoing thyroidectomy for a solitary solid thyroid nodule in an 4-year period. The diagnoses were classified as indeterminant, benign, or malignant. The utility and impact of the diagnosis from fine-needle aspiration or frozen section on the operative procedure performed was analyzed. Fine-needle aspiration cytology as a diagnostic test for thyroid nodules demonstrated an indeterminant rate of 23 per cent, with a diagnostic accuracy of 77 and 92 per cent for benign and malignant disease, respectively. In all patients with inaccurate benign diagnosis on fine-needle aspiration cytology, follicular neoplasm was misinterpreted for follicular adenoma or multinodular goiter. In comparing frozen-section results, the indeterminant, benign, and malignant rates were 7, 96, and 64 per cent, respectively. Of the 23 patients with indeterminant results on fine-needle aspiration cytology, the intraoperative frozen-section diagnosis on 4 patients was deferred to permanent section; 18 received accurate cytological diagnosis; and in 1 patient, carcinoma was missed. Overall, the decision about the extent of surgical thyroid resection was changed in only 2 patients based on the frozen-section results. Preoperative evaluation with fine-needle aspiration cytology can accurately and appropriately define the extent of thyroid surgery in most patients with a diagnosis of malignant neoplasm or benign disease. Intraoperative frozen-section examination may be helpful if fine-needle aspiration cytology results are inderminant and in cases of follicular histology as an adjunct for evaluation of the thyroid nodule, but overall, frozen section does not contribute to the management of the thyroid lesion at the time of surgery.     

Laparoscopic surgery in Crohn's disease

In a prospective study the feasibility and safety of laparoscopic-assisted ileocaecal resection for Crohn's disease was studied and compared with 16 patients who had open ileocaecal resection, and the value of laparoscopic stoma surgery was assessed. From January to November 1995 laparoscopic-assisted ileocaecal resection for Crohn's disease was undertaken in 7 patients, laparoscopic-assisted stoma formation in 10 patients. In 1 patient laparoscopic ileocaecal resection was converted to open surgery due to an unrecognised ileocolic fistula. Operating time in laparoscopic-assisted ileocaecal resections was longer than in open ileocaecal resection (150 vs. 127 min, P = 0.7). Blood loss (386 vs. 445 ml, P = 0.7), first bowel movement (3.5 vs. 4.9 postoperative days, P = 0.07) and postoperative time to discharge (5.2 vs. 9.9 days, P < 0.01) in patients who had a laparoscopic-assisted ileocaecal resection were less than in patients who had open surgery. In all 10 patients laparoscopic formation of a stoma was possible. Operating time was 62 min. Oral solids were restored on the 1.5 postoperative day. Mean postoperative stay was 8.8 days, prolonged due to time needed for stoma-care training. These preliminary results indicate that laparoscopic-assisted ileocaecal resection and stoma surgery for Crohn's disease are feasible and safe. Both procedures are characterised by rapid recovery and superior cosmetic results.     

The new temperance movement in the United States: what happened to macrostructural factors in alcohol problems?

BACKGROUND: Pulmonary tuberculosis can produce unusual radiographic appearances and negative results of sputum and bronchoscopic examinations are common. This study assessed the value of ultrasound guided aspiration biopsy in the diagnosis of pulmonary tuberculosis with unusual radiographic appearances. METHODS: Thirteen patients, ultimately diagnosed as having tuberculosis, underwent a chest ultrasonographic examination between June 1984 and August 1991. All had sputum available for examination and nine were also examined by bronchoscopy. Ten patients who had a negative sputum smear and negative bronchoscopic brushing smears underwent ultrasound guided aspiration or biopsy. Percutaneous aspiration was performed with a 22 gauge needle. If the smear did not reveal acid fast bacilli, a biopsy sample was taken with a 16 gauge Tru-cut needle to obtain a histological diagnosis. RESULTS: The ultrasonographic examination delineated the more complex nature of the lesions better than the chest radiograph. Ultrasound guided aspiration biopsy provided the diagnosis in nine of 10 patients, while the sputum smear and culture provided diagnosis in five of 13, and bronchoscopy in four of nine. In terms of rapid diagnosis, ultrasound guided aspiration biopsy gave the diagnosis in eight of 10 cases. No patient developed a major complication. CONCLUSION: Ultrasonography can direct the needle to the most suitable part of a lesion to obtain the relevant specimens. The diagnostic yield is high and the procedure is relatively safe. It is especially helpful in patients with negative results of sputum and bronchoscopic examinations.     

Solitary thyroid nodule in Khartoum

Ninety four patients with solitary and significantly dominant thyroid nodules were studied. Inadequate sampling was reported in 5 patients (5.9%). In the remaining 89 patients, 64 had simple goitre (72%), 12 follicular adenoma (13.5%), 12 were malignant nodules (6 follicular, 5 papillary and one anaplastic) (13.5%) and one patient had Hashimoto's thyroiditis. The incidence of malignancy in the clinically solitary nodules was 14% (10/70) compared to 10% (2/19) for the dominant nodules which increased to 16% (8/49) versus 10% (4/40) respectively after ultrasonography and histopathological confirmation of the nature of the gland. There is a low positive predictive value for follicular neoplasm with fine needle aspiration cytology (FNAC) (44%). This is due to the fact that reports of suspicious follicular pattern is agreed not to imply definite malignancy, however total lobectomy was done for those patients whereas terms like "not suspicious" and "highly suspicious" are considered to mean, benign and malignant respectively and in those latter groups the prediction was 100%. The study stresses the importance of FNAC techniques in reducing the surgical load with minimal false negative results, increasing the yield of carcinoma and projecting the importance of a significantly dominant nodule in endemic areas.     

Possible relation of osteopontin to development of psammoma bodies in human papillary thyroid cancer

Fine-needle aspiration cytology (FNAC) is the most useful procedure for the evaluation of thyroid nodules. The requirement for repeated aspirations in the follow-up of benign nodular thyroid disease, however, is controversial. To determine the value of re-aspirations in benign nodular thyroid disease, we studied 457 fine-needle reaspirations performed on 216 patients (197 female, 19 male) aged 42.9+/-12 years with uninodular (n = 65) and multinodular (n = 151) thyroid disease. Two hundred fifty-seven of these were second, 137 were third, 46 were fourth, and 17 were fifth re-aspirations of the same nodule, performed in a mean follow-up time of 43.9+/-31 (3-156) months. FNAC results were benign in 407 (89%), insufficient for diagnosis in 31 (6.8%), suspicious in 16 (3.5%), and papillary carcinoma (PC) in 3 (0.7%). An initial benign diagnosis did not change after multiple aspirations in 213 (98.61%) of the cases. Three patients with initial aspirations read as benign had a diagnosis of PC from their second biopsies, (diagnosis confirmed at surgery). Re-examination of the initial FNAC revealed atypical features in 1 of the 3 patients. These 3 patients likely represent a false-negative result of the initial FNAC rather than benign nodular disease transformed to a malignant one during the follow-up period. In conclusion, a second aspiration of clinically suspicious nodules may correct a few initial false-negative results, but routine additional re-aspirations are not useful for clinically stable disease.     

Argyrophilic nucleolar organiser regions (AgNORs) in breast lesions

Nucleolar organiser regions (NORs) demonstrated by argyrophilia of NOR-proteins are indicator of cellular proliferative activity. The NORs can be identified in the nuclei as brown or black dots with silver colloidal staining technique in formalin fixed paraffin sections and in cytology smears. Seventy-five cases including 45 tissue sections and 30 fine needle aspiration cytology (FNAC) smears of benign and malignant lesions of breast have been studied to evaluate the significance and practical application of AgNOR count per nucleus. Out of 45 tissue sections 15 belonged to fibrocystic disease, 10 fibro-adenomas and 20 carcinomas and of the 30 FNAC smears, 10 were fibrocystic disease, 8 fibro-adenomas and 12 carcinomas. In fibrocystic disease the mean AgNOR count was 1.60 (FNAC group-0.75, tissue section-1.61). In fibro-adenomas it was 1.61 (FNAC-1.63, tissue section-1.59). The mean count in carcinoma was 12.10 (FNAC-12.08, tissue section-12.10). The difference in AgNOR count in fibrocystic disease and fibro-adenoma was not significant, but that between benign breast lesion and carcinoma was significant. No difference was observed between FNAC and tissue section groups in benign or malignant lesions. The simple staining technique can be used as an additional criterion to differentiate the benign and malignant lesions of breast.     

Intrabiliary growth of metastatic colonic adenocarcinoma: a pattern of intrahepatic spread easily confused with primary neoplasia of the biliary tract

Because of its propensity to spread along epithelial surfaces, colonic adenocarcinoma can mimic other neoplasms. For example, colonic adenocarcinoma can grow along the surface of the urinary bladder and can simulate primary bladder neoplasia, and metastatic colonic adenocarcinoma can grow along alveolar walls and can mimic primary lung neoplasia. Intraepithelial spread along bile ducts, however, is not a well-recognized behavior of hepatic metastases. Indeed, dysplastic change in the epithelium lining the biliary tract is sometimes used to discriminate primary biliary neoplasms from metastatic adenocarcinoma. We report on eight cases of colonic adenocarcinoma metastatic to the liver that demonstrated prominent spread throughout the biliary tree along intact basement membranes. Morphologically, this pattern closely resembled high-grade dysplasia (i.e., carcinoma in situ) of the extrahepatic and intrahepatic bile ducts. Clinically, two of the tumors were mistaken for primary biliary neoplasia because of the common radiologic finding of intrabiliary masses with distended bile ducts. A definite diagnosis of metastatic carcinoma was established by careful attention to the medical history, thorough evaluation of the morphologic features, and histologic comparison with the primary colon cancer. For patients with a history of colonic adenocarcinoma, consideration of a liver metastasis is appropriate even when certain histologic and radiographic features point to a neoplasm of biliary origin.     

Avulsion of the flexor digitorum profundus tendon associated with a chondroma of the distal phalanx

Sarcoma of the penis is rare. We report an angiosarcoma that was essentially an incidental finding, despite the presence of metastatic lesions, in a 46-year-old man who presented with hematemesis and melena. The diagnosis of the primary lesion was confirmed by histology, and the presence of secondary lesions by fine needle aspiration cytology. The patient was given one dose of chemotherapy, but died of a myocardial infarction before being able to receive further treatment. The literature pertaining to this very unusual lesion is discussed.     

Tuberculous colitis mimicking Crohn's disease

Intestinal tuberculosis is a rare disease in western countries and may mimic a variety of gastrointestinal disorders. Here, we report the case of a 63-yr-old patient who presented with profuse bleeding from a deep rectal ulcer. Similar lesions were found in different parts of the colon. Multilocular colorectal carcinoma was suspected based on the macroscopic appearance. Histology, however, suggested Crohn's disease. Intestinal tuberculosis was initially ruled out by negative staining for acid-fast bacilli, mycobacterial culture, and polymerase chain reaction analysis. A treatment for Crohn's disease was started. Endoscopic reexamination revealed progressive disease with extensive ulcerations of the terminal ileum. Histopathological examination then revealed acid-fast bacilli in the colonic mucosa typical for mycobacterium tuberculosis infection. This case emphasizes the need to include intestinal tuberculosis in the initial differential diagnosis of ulcerative colorectal lesions also in the western population.     

What''s new in cosmetic surgery of the hand? Technical notes]

INTRODUCTION: Any breast lesion/abnormality detected at mammography must be characterized as (non)-neoplastic before surgery. Fine needle aspiration cytology (FNAC) permits a precise diagnosis in over 70% of cases but exhibits many inadequate, false negatives or questionable findings. This makes surgical biopsy mandatory in many cases. An alternative is offered by fine needle biopsy (FNB: 16-18 G needles) or by large core biopsy (LCB: 14 G needles), which procedures can reduce the number of questionable diagnoses with no major discomfort or side-effects for the patient. MATERIAL AND METHODS: January, 1996, to October, 1997, we performed 422 microhistologic biopsies on breast lesions at the Unità Integrata di Senologia, Azienda Ospedaliera Careggi, Florence, Italy. 383 of these lesions were nonpalpable. FNB was performed in 221 cases and LCB in 201. Most biopsies (65%) were carried out under US guidance and some others (25%) under stereotactic guidance. RESULTS: Microhistologic biopsy allowed accurate lesion characterization in most cases, even though LCB obviously performed much better. Samples were inadequate in 5.88% of cases with FNB and only in 2.98% of cases with LCB. The false negative rate was 1.92% for FNB and 0.99% for LCB. Surgical biopsy was needed for an unquestionable diagnosis only in 9.5% of FNB and 3.9% of LCB cases. CONCLUSIONS: Our results confirm the literature data on how LCB can be considered a valid alternative to surgical biopsy (and, to some extent, to FNAC); in particular, its advantages are: moderate invasiveness, little patient discomfort and high diagnostic accuracy. Moreover, the procedure is short (5-10 minutes) and costs much less than surgical biopsies (1/2 to 1/4).     

Signet-ring cell melanoma mimicking adenocarcinoma. A case report

The fine needle aspiration findings in a lymph node involved by signet-ring cell melanoma, a very rare variant of malignant melanoma, are reported. The patient had a history of superficial spreading melanoma of the right foot, treated 10 years earlier by below-the-knee amputation. He presented with a right groin mass. Fine needle aspiration of the mass yielded poorly cohesive, large cells with eccentric nuclei and abundant, eosinophilic cytoplasm; many of them exhibited a signet-ring appearance. Melanin pigments were identified in a small proportion of tumor cells, and a diagnosis of metastatic melanoma was made. The subsequent lymph node excision revealed a metastatic tumor composed of polygonal and signet-ring cells that were positive for S-100 protein and HMB-45 but not cytokeratin. Nearly all reported cases of signet-ring cell melanoma occurred as metastatic or recurrent disease. It is important not to mistake signet-ring cell melanoma for adenocarcinoma in aspiration cytology, and a constellation of clinical features and of histochemical and immunohistochemical findings enables a correct diagnosis to be reached.