Sarcomas of the stomach

Sarcomas of the gastric wall, other than lymphomas, are a heterogeneous group of stromal malignant neoplasms composed of round and spindle cells. Many are malignant forms of epithelioid leiomyoma. Small cell size, high cellular density, a high rate of mitotic activity, and cellular pleomorphism are helpful clues in distinguishing malignant from benign gastric stromal tumors. Sarcomas of the stomach are aggressive, rapidly growing neoplasms. Among 44 examples metastasis occurred in three-fourths of the patients, usually within the first year after diagnosis.     

Eruptive epithelioid hemangioendothelioma with spindle cells

A 39-year-old white man presented with four discrete dermal nodules in his right upper arm. Biopsy revealed superficial dermal well-circumscribed nodules composed of solid areas and vascular spaces lined by epithelioid endothelial cells and a similar nodule composed of spindle and epithelioid cells. A moderate mitotic count of 3-4 mitoses/10 hpf was present. Multiple lesions erupted 1 month later distally and proximally to the original lesions. Magnetic resonance imaging of the right arm demonstrated a lesion in the humerus. Biopsy of the humerus showed a vascular tumor with similar histologic features to the overlying skin lesions. The differential diagnosis included epithelioid vascular tumors, bacillary angiomatosis, pyogenic granuloma, and Kaposi sarcoma. Vascular lesions containing epithelioid and spindle cells span a spectrum from benign to malignant. We believe these tumors belong in the category of hemangioendothelioma and propose the name eruptive epithelioid hemangioendothelioma with spindle cells. Our case emphasizes that eruptive cutaneous vascular lesions do not always suggest immunosuppression or malignancy. Additionally, it highlights the association between epithelioid vascular lesions of the skin and bone.     

Few microorganisms associated with bacterial vaginosis may constitute the pathologic core: a population-based microbiologic study among 3596 pregnant women

OBJECTIVE: To evaluate if pelvic magnetic resonance imaging (MRI) is reliable for differentiating leiomyoma subtypes. DESIGN: Prospective study. SETTING: Academic center. PATIENT(S): Forty-five patients underwent MRI before surgery for leiomyomata. INTERVENTION(S): One radiologist blinded to patient history and histologic diagnosis recorded the MRI characteristics and classification of the largest leiomyoma. MAIN OUTCOME MEASURE(S): Comparison of MRI and histologic diagnoses. RESULT(S): Leiomyoma subtypes were diagnosed accurately by MRI in 69% of cases. Magnetic resonance imaging had a 95% sensitivity and 72% specificity for diagnosing an uncomplicated leiomyoma and a 10% sensitivity and 100% specificity for a cellular leiomyoma. For cystic leiomyomata, the sensitivity was 80% and specificity was 98%, and for hemorrhagic leiomyomata, 100% and 86%, respectively. Magnetic resonance imaging correctly diagnosed all malignant tumors and did not incorrectly diagnose a leiomyoma as a leiomyosarcoma in any case. Ill-defined MRI margins were significantly more likely to be leiomyosarcoma, whereas well-defined margins were characteristic of benign lesions. Hemorrhagic leiomyomata were significantly more likely to be hyperintense on T1-weighted images than other subtypes. CONCLUSION(S): Although MRI is only fairly accurate in differentiating the subtypes of benign uterine smooth muscle tumors, signal intensities and margin characteristics are useful to distinguish accurately benign from malignant tumors.     

Atypical scrotal leiomyoma. A case report

A case of intrascrotal atypical leiomyoma is reported. This lesion is extremely rare and usually misdiagnosed. Microscopically, contain bizarre and pleomorphic tumor cells, as well as showed immunohistochemical evidence of smooth muscle differentiation. An important microscopic criterion in the distinction with other entity, as the leiomyosarcoma, is the number of mitotic figures, scarce in the atypical leiomyoma and high in the smooth muscle tumours malignant.     

Assessment of diagnostic utility of anti-CD34 in soft tissue tumors

We have performed this study to define the usefulness of an anti-human progenitor cell antigen-1(anti-CD34) to distinguish some kinds of soft tissue tumors in formalin-fixed, paraffin-embedded tissues. Sixty three cases of vascular, fibrohistiocytic, neural and other tumors were immunostained for CD34 using the streptavidin-biotin immunoperoxidase method. All of the vascular tumors including hemangiomas, epithelioid hemangioendotheliomas, hemangiopericytomas, and lymphangiomas revealed strong CD34 positivity along the cytoplasmic membranes. Among the fibrohistiocytic lesions, all of five examples of dermatofibrosarcoma protuberans showed diffuse, strong, and linear staining along the cytoplasmic processes. In contrast, none of the benign fibrous histiocytomas and malignant fibrous histiocytomas expressed CD34. CD34-positive cells with delicate dendritic processes could be identified within the normal nerves, neuromas, neurofibromas, and Antoni B areas of neurilemomas. However, all of the malignant peripheral nerve sheath tumors were uniformly negative. In addition, an epithelioid sarcoma and four cases of leiomyosarcoma revealed focal, weak positivity with anti-CD34. In conclusion, this study demonstrated variable anti-CD34 staining pattern of certain fibrohistiocytic, muscle, and neural tumors and confirmed the potential usefulness of anti-CD34 in differentiating fibrous histiocytoma from dermatofibrosarcoma protuberans. It's also helpful to diagnose epithelioid hemangioendothelioma from other epithelioid-type tumors.     

Stromal tumors of the jejunum and ileum: a clinicopathologic study of 39 cases

Recently, cell size, cell density, and growth pattern were found to be reliable histologic parameters in separating benign from malignant duodenal stromal tumors. However, there are few data on the histologic features and important prognostic parameters of stromal tumors from other parts of the small bowel. Thus, we studied the clinical and pathologic features of 39 stromal tumors of the jejunum and ileum to determine which parameters would be most useful in distinguishing a benign from a malignant tumor. In all cases, the following histologic parameters were recorded: (a) predominant growth pattern (organoid, fascicular, solid, or mixed), (b) cellularity (low or high), (c) predominant cell type (spindled, epithelioid, or mixed), (d) nuclear pleomorphism (minimal, moderate, or severe), (e) the presence or absence of tumor cell necrosis, (f) the presence or absence of mucosal infiltration, (g) the presence or absence of skeinoid fibers, and (h) the number of mitotic figures per 50 high-power microscopic fields (HPF). Clinical follow-up was obtained in all cases, and the patients were considered to have suffered an adverse outcome if they developed metastatic disease or died as a complication of their tumor. In the absence of these features, patients were not considered to have suffered an adverse outcome. Twenty-five patients suffered an adverse outcome. Twenty-one patients died of disease from 1 month to 9 years (median: 2 years). One patient died at 4 days because of postoperative complications. Three patients were alive with metastatic disease at 6 months, 6 years, and 7 years. Twenty-four of these 25 patients developed metastatic disease, most commonly to the liver. Fourteen patients did not suffer an adverse outcome. Eleven patients were alive without disease from 2 to 11 years (median: 3 years), and three patients died of unrelated causes at 1, 1, and 3 years. Although there was some overlap in features between clinically benign and malignant tumors, features that were significantly associated with an adverse outcome included tumor size > 5 cm, mitotic counts > 5 mitotic figures per 50 HPF, high cellularity, the absence of a predominant organoid growth pattern, the absence of skeinoid fibers, the presence of severe nuclear pleomorphism, and the presence of mucosal infiltration and tumor cell necrosis (p < 0.05 using the chi-square and Fisher's exact tests). Features that were significantly associated with decreased survival included tumor size > 5 cm, mitotic counts > 5 mitotic figures per 50 HPF, high cellularity, the absence of skeinoid fibers, and the presence of tumor cell necrosis (p < 0.05 using the Mantel-Haenszel log-rank test). Given the fact that there is some overlap in these features between clinically benign and malignant tumors, a multiparametric analysis using the above features is the most effective way of predicting clinical behavior.     

Laparoscopic resection of gastric leiomyoblastoma

Smooth muscle gastric tumors represent 2% of resected neoplasms of the stomach. Clinically, they are often silent and incidentally found at endoscopy or radiologic examination. These tumors can be histologically classified as benign (leiomyoma) or malignant (leiomyoblastoma), but clinical behavior is not strictly related to this classification. When symptomatic, they are present with anemia in 50% of cases due to mucosal ulceration. Surgical removal of the tumor is the accepted therapy, leaving a margin of surrounding free tissue: this treatment can be performed by laparoscopy, usefully associated with gastroscopy. We present one case of a patient with severe anemia due to bleeding from an ulcerated leiomyoblastoma 5 cm in diameter that we resected with combined gastroscopic-laparoscopic technique. We isolated the portion of gastric wall where the mass was located and resected the specimen under gastroscopic control. The postoperative period was uneventful, and the patient recovered promptly with minimal pain and discomfort.     

Minimally invasive management of low-grade and benign gastric tumors

BACKGROUND: Benign gastric tumors and tumors of low-grade malignancy can be safely removed laparoscopically. METHODS: Seven patients were considered candidates for laparoscopic resection of gastric tumors. Inclusion criteria included small tumor size (less than 6 cm), exophytic or endophytic tumor morphology, and benign characteristics. Indications for surgical intervention included bleeding, weight loss, and need for tissue diagnosis. Patients ranged in age from 38 to 70. There were five female and two male patients. All patients underwent preoperative upper GI endoscopy. The procedures were performed using a four- or five-port technique. An Endo-GIA (US Surgical Company, Norwalk, Connecticut) was used to amputate those tumors located on the serosal surface of the stomach. Tumors on the mucosal surface were exposed via a gastrotomy, then likewise amputated using an Endo-GIA. The gastrotomy closure was then either hand sewn or stapled. Operating time ranged from 95 to 225 min. RESULTS: Final pathologic diagnoses included lipoma, lymphoma, leiomyoma, and leiomyosarcoma. There was a 28% conversion rate. There were no complications. Length of postoperative stay ranged from 4 to 7 days. There have been no tumor recurrences in 6-38-month follow-up. CONCLUSIONS: Minimally invasive management of benign and low-grade gastric tumors can be performed safely with excellent short- and long-term results.     

The stepchild of intestinal diagnosis. Evaluation of radiologic methods in the diagnosis of leiomyoma of the small intestine

PURPOSE: Various radiological methods to diagnose small bowel neoplasms and problems of differential diagnosis specially considering leiomyomas are discussed. PATIENTS AND METHODS: Two patients with leiomyoma of the ileum underwent enteroclysis, computed tomography of the abdomen, intra-arterial DSA and colour Doppler sonography. Another patient with leiomyosarcoma just underwent CT of the abdomen with CT-guided biopsy. RESULTS: Due to the homogenous density and the smooth surface of the tumors in computed tomography and respectively enteroclysis and the presentation of the tumor vascularisation in the angiography and Colour Doppler sonography in both patients a leiomyoma of the small bowel was diagnosed. Postoperatively this diagnosis was histologically confirmed. The CT-findings of the patient with leiomyosarcoma were not suspicious of a malignant tumor. CONCLUSION: Radiologically it is not possible to determine the dignity of smooth muscle cell tumors safely. That is the reason why the diagnosis has to be achieved operatively. But the histopathological diagnosis based on the mitotic rate may be difficult. Therefore the after care has to be carried out thoroughly.     

Epithelioid smooth-muscle tumors of the uterus: a clinicopathologic study of 18 patients

Epithelioid smooth-muscle tumors of the uterus are uncommon neoplasms for which prognostic factors have not been well established. A retrospective follow-up study of 18 uterine epithelioid smooth-muscle tumors was performed. Patients ranged in age from 27 to 83 years (mean, 45 years) and were separated into three groups based on the nuclear grade of the epithelioid tumor cells. Two tumors had grade 1 nuclei; both were examples of intravenous leiomyomatosis. They had highest mitosis counts of 1 and 3 mitotic figures (MF)/10 high-power fields (HPF), no tumor cell necrosis was found, and both patients were alive with no evidence of disease at 64 and 5 months' follow-up. Ten tumors had grade 2 nuclei. All had highest mitosis counts of 0 to 3 MF/10 HPF, except one (5 MF/10 HPF). Tumor cell necrosis was absent in nine and only one had an infiltrative border. Tumor size ranged from 1.5 to 14 cm. Two tumors contained pleomorphic ("symplastic") multinucleated giant cells similar to those seen in bizarre leiomyomas. All nine patients with follow-up were alive with no evidence of disease 5 to 203 months postoperatively (median, 74 months). One patient had also received adjuvant radiation therapy. Six tumors had grade 3 nuclei. Highest mitosis counts of 4 to 9 MF/10 HPF were found in five; one had 1 MF/10 HPF. Maximum tumor size ranged from 4.5 to 13 cm. Two had tumor cell necrosis, and two had an infiltrative border. Two of these patients died of tumor 11 and 132 months postoperatively. The former had widespread metastases at initial surgery (stage IVb); the latter patient (stage I) developed the first of seven tumor recurrences 3 years postoperatively. Both patients had also received adjuvant chemotherapy. Of the remaining four patients, two were alive with no evidence of disease at 48 and 83 months, one was alive (tumor status unknown) at 28 months, and one was lost to follow-up. Based on our findings and those in the literature, we conclude that uterine smooth-muscle tumors with a predominance of epithelioid cells are extremely uncommon and metastasize infrequently. No single histologic feature is predictive of metastatic potential. Clinically malignant tumors (i.e., epithelioid leiomyosarcomas) typically have the combination of significant nuclear atypia (either grade 2 or grade 3 nuclei) and some mitotic activity (usually at least 3 to 4 MF/10 HPF); most also have tumor cell necrosis.     

Leiomyosarcoma of the kidney in an HIV-infected child

Spindle cell tumors (leiomyoma and leiomyosarcoma) have been described in immunocompromised children after transplantation and in association with HIV infection. Previous reports have described tumors of respiratory (lung, bronchi), gastrointestinal (stomach, bowel, liver), and subcutaneous origins. We report a case of leiomyosarcoma of the kidney in an HIV-infected child.     

Gastric schwannoma

A rare case of gastric schwannoma is reported. A 36-year-old woman whose endoscopy showed a mucosa tumor, biopsy findings were suggestive for leiomyoma. Diagnosis was made only with postoperative histology that revealed the benign schwannoma. Immunohistochemical staining showed positivity for S-100 protein and the neuron specific enolase, schwannoma is often associated with Von Recklinghausen's disease. Surgical resection is recommended as their malignant potentiality. Gastric and small intestine localizations are often with bleeding. They also represent almost the 24% of all gastrointestinal stromal tumors (GIST) and the 4% of all primary retroperitoneal tumors.     

D2 receptor binding in dopa-responsive dystonia

OBJECTIVES: Synchronous gastric tumors (including benign and secondary tumors) associated with esophageal cancer present diagnostic and therapeutic issues. We investigated this synchronous association, and retrospectively determined the frequency of the gastric tumors and the clinical characteristics. METHODS: In a series of 208 patients with esophageal cancer, we investigated the synchronous gastric tumors, as well as the frequency of association, clinicopathological characteristics, diagnosis, treatment, and the clinical outcome after surgery. RESULTS: Twenty-eight gastric tumors were found in 24 patients. Adenocarcinoma was most frequent. Most of these tumors were located at the upper or middle third of the stomach. Eight gastric tumors in six patients could not be detected preoperatively. Six of these tumors including a gastric remnant cancer were detected in the resected stomach, and two leiomyomas were detected during the operation. In one patient in which an endoscope could not pass through the esophagus, a leiomyoma was detected in the resected stomach. For the gastric cancers, total gastrectomy or proximal gastrectomy with lymph node dissections was performed. For the benign tumors, partial resection of the stomach was performed, and endoscopic resection was performed preoperatively for an adenoma. In both the postoperative hospital mortality rate and the survival rate after surgery, there were no significant differences between the patients with and without gastric tumors. CONCLUSIONS: Synchronous gastric tumors associated with esophageal cancer are not rare. When an endoscope cannot pass through the esophagus before surgery, other techniques must be performed to explore the stomach. For these patients, surgical treatment should be adapted positively.     

"Proximal-type" epithelioid sarcoma, a distinctive aggressive neoplasm showing rhabdoid features. Clinicopathologic, immunohistochemical, and ultrastructural study of a series

Eighteen examples of an unusual malignant soft-tissue neoplasm, the morphology of which ranged from that of "atypical" epithelioid sarcoma to that of a rhabdoid tumor or undifferentiated carcinoma (with transitional forms) are described. Patients included 11 males and seven females; their median age was 35.5 years with most patients aged 20 to 40 years. Development of a mass was the main presenting symptom. Six tumors developed in the pelvis and perineal region, four in the pubic region and vulva, three in the buttocks, one in the deep soft tissues of the left hip, one on the penis, one in left forearm, one in left axilla, and one on the occiput. Tumor size ranged from 1 to 20 cm (median, 4 cm). On microscopic examination, the tumor cells invaded the subcutaneous or deep soft tissues, had prominent epithelioid or rhabdoid features, had marked cytologic atypia, and grew in a multinodular pattern in half of the cases. Areas of necrosis were often seen. A granuloma-like pattern reminiscent of that observed in classic epithelioid sarcoma was observed in only two cases. Immunohistochemically, positivity for cytokeratin, epithelial membrane antigen, and vimentin was seen in all but one of the cases. Of 16 cases, 10 and eight tumors reacted with desmin and CD34, respectively; five of 15 reacted at least focally with smooth-muscle actin, whereas three of 13 and one of 10 reacted for HMB-45 and carcinoembryonic antigen, respectively. S-100 protein and CD31 yielded negative results. Seven tumors were investigated at the ultrastructural level, four of which showed prominent intracytoplasmic intermediate filament aggregates, often accumulating into paranuclear whorls, which is in keeping with the rhabdoid phenotype. Five tumors showed features of epithelial differentiation (i.e., tonofilament-like structures or desmosomes or both), whereas one tumor displayed features of myofibroblastic differentiation. Differential diagnoses include mainly conventional epithelioid sarcoma, extrarenal malignant rhabdoid tumor, epithelioid malignant peripheral nerve sheath tumor, melanoma, rhabdomyosarcoma, and undifferentiated carcinoma. Follow-up information on 14 patients (range, 4 months to 8 years; median, 19 months) revealed local recurrence in one case and metastatic dissemination in six patients, leading to death in five. In our opinion, the above-described neoplasms represent a usually "proximal-type" of epithelioid sarcoma. In contrast to the conventional, "distal-type" epithelioid sarcoma, the proximal variant is characterized by a predominantly large-cell, epithelioid cytomorphology, marked cytologic atypia, frequent occurrence of rhabdoid features, and lack of a granuloma-like pattern in most cases. It appears to be somewhat more aggressive (or at least metastasizes earlier) than usual epithelioid sarcoma.     

Two cases of gastric involvement of esophageal cancer: intramural metastasis and intramural lymph node metastasis

Cases of esophageal cancer with intramural metastasis to the stomach and esophageal cancer with metastasis to an intramural lymph node of the stomach are herein reported. The former patient was a 52 year-old male. Squamous cell carcinoma (SCC) of the lower esophagus with an intramural metastasis located at the gastric cardia and a small leiomyoma at the fornix were resected. The latter patient was a 70 year-old female. SCC of the lower esophagus and an intramural lymph node metastasis located at the anterior wall of the gastric cardia were resected. The patient died nevertheless of multiple liver metastases. These gastric involvements were detectable by endoscopy before surgery. The clinicopathological features of these esophageal cancers were characterized; the sites were the lower part of the esophagus, and extreme lymphatic and vascular invasions were shown histologically. The gastric tumors were located in the upper third of the stomach, and the findings revealed submucosal tumors. It is therefore important to discriminate other gastric tumors, and to resect them simultaneously with esophageal cancer when a gastric tube has been used for reconstruction after esophagectomy.     

Solitary fibrous tumour of the tongue

In a review of pulmonary tumors diagnosed at our institute from 1976 to 1995, we found 20 malignant and 12 benign rare tumors, which accounted for 0.57 and 0.34% of all pulmonary tumors, respectively. The histological types of these rare malignant tumors were malignant lymphoma (6/20), carcinosarcoma (3/20), mucoepidermoid carcinoma (2/20), bronchial gland mixed tumor (2/20), adenocystic carcinoma (1/20), myoepithelioma (1/20), leiomyosarcoma (1/20), epitheloid hemangioendothelioma (1/20), hemangiopericytoma (1/20), malignant melanoma (1/20) and choriocarcinoma (1/20). Benign rare tumors involved papilloma (3/12), lipoma (3/12), leiomyoma (3/12), adenoma (1/12), fibroma (1/12), and meningioma (1/12). The clinical and pathological features of malignant tumors were roughly the same as those of common pulmonary carcinomas. In contrast, benign tumors were never larger than 3 cm and were more commonly located in the central parts of the lung, which explained the relatively frequent symptoms of wheezing and fever associated with obstructive pneumonia.     

BRCA1 splice variants BRCA1a and BRCA1b associate with CBP co-activator

PURPOSE: To define the appearance of gastric stromal sarcomas at magnetic resonance (MR) imaging. MATERIALS AND METHODS: Nine patients with gastric stromal sarcoma underwent MR imaging with the following sequences: nonenhanced and gadolinium-enhanced breath-hold, T1-weighted, spoiled gradient-recalled echo (n = 9); fat-suppressed, T2-weighted, fast spin echo (n = 9); and breathing-independent, half-Fourier rapid acquisition with relaxation enhancement (n = 6). Lesion morphology, signal intensity features, and relationships to the gastric wall and surrounding organs were retrospectively evaluated. The diagnosis of gastric stromal sarcoma was histologically proved in all patients. RESULTS: The nine tumors were solitary, multilobulated, shaped irregularly, predominantly exophytic, and large (diameter range, 7-28 cm [mean, 15.8 cm]). The epicenters of all lesions were extrinsic to the stomach, and all lesions arose from the gastric cardia or body. Regions of necrosis and hemorrhage were detected in all cases. Marginal definition on MR images corresponded to histologic grade: High-grade neoplasms possessed ill-defined margins, and low-grade neoplasms demonstrated more well-defined margins. Relationships to surrounding organs depicted at MR imaging corresponded well with histopathologic findings. CONCLUSION: Gastric stromal sarcomas demonstrate characteristic MR imaging features, which correspond well with histopathologic findings. The direct multiplanar capability of MR imaging facilitates delineation of relationships of the tumors to the stomach and surrounding organs.     

Epithelioid leiomyosarcoma of the stomach with hemorrhagic ascites

In two men (69 and 65 years old) a gastric epithelioid leiomyosarcoma more than 25 cm in diameter first manifested itself by an increase in abdominal girth and ascites. In case 1, a cylindrical mass was palpable in the abdomen increasing in size over two years. Sonography and computed tomography showed a large cystic tumour which could not be related to any one organ. Cytology of the ascites fluid did not reveal any tumour cells. At operation a pedunculated tumour, 29 x 20 x 9 cm, was found, originating from the stomach. Six litres of ascites fluid were aspirated. There were no detectable abdominal metastases. The patient died nearly 4 years later after the tumour had been resected, three further laparotomies had to be performed because of extensive metastases to peritoneum and liver from the leiomyosarcoma. In case 2, no abdominal mass was palpable, but the patient's girth had increased over the last year. Sonography revealed a cystic tumour, about 30 cm in diameter. Examination of haemorrhagic ascites fluid (700 ml) did not show any tumour cells. The tumour, originating from the stomach wall, was excised (no metastases were seen). The patient remains symptom-free after 35 months.     

Osteochondromalike parosteal osteosarcoma: a report of six cases of a new entity

OBJECTIVE: Our purpose was to describe a rare juxtacortical bone sarcoma with deceptively benign, osteochondromalike histologic characteristics. We present criteria by which this low-grade malignant neoplasm can be distinguished from other benign and malignant surface lesions of bone with particular emphasis on the imaging features. MATERIALS AND METHODS: Six cases of a low-grade, chondroossifying parosteal sarcoma of bone were reviewed. Patients included four males and two females 11 months to 66 years old. Histologic findings from initial tumors and from recurrent tumors were reviewed. Two musculoskeletal radiologists analyzed the imaging studies, which included plain films, CT scans, MR images, and a bone scan. RESULTS: Histologically, the lesions were characterized by a thin layer of proliferating, periosteally derived spindle cells overlying a thin, low-grade malignant cartilage cap that underwent calcification, neovascularization, and conversion into benign bone and marrow fat. These lesions were unique in that the malignant elements were only at their periphery. All six cases were initially misdiagnosed as benign lesions on pathologic evaluation. In each patient, imaging revealed a "pasted-on" ossified surface lesion with an intact underlying cortex and no medullary involvement. In three cases, recurrent tumors had histologic appearances consistent with conventional parosteal osteosarcoma. Dedifferentiation, metastases, and death occurred in one of these three cases. CONCLUSION: To our knowledge, this surface lesion of bone has not been specifically described. Whether this tumor constitutes a distinct entity or is a specialized variant of parosteal osteosarcoma is unclear. Precise radiologic-pathologic correlation is essential for appropriate diagnosis and management.