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Clear cell sarcoma shares features with melanoma, but frequently shows EWSR1 rearrangements. It is an aggressive tumor typically occurring in the soft tissues of the extremities, with a gastrointestinal variant with less consistent melanocytic differentiation. It is extremely rare in the head and neck region, with no reported cases in the oral cavity. We report a case of an 82-year-old woman with a clear cell sarcoma arising in the tongue, with cervical lymph node metastases. Histologically, the tumor showed some features of gastrointestinal clear cell sarcoma. No osteoclast-type giant cells were present. The tumor cells were positive for S100 protein and negative for other melanocytic markers. Fluorescence in situ hybridization showed rearrangements of EWSR1 and ATF1. This case expands the spectrum of clear cell sarcoma with a gastrointestinal-like variant in a novel site, emphasizing the need to consider it as a differential diagnosis to melanoma in mucosal sites. [ABSTRACT FROM AUTHOR]

The article offers protocols developed by the College of American Pathologists that will help pathologists in reporting clinically useful and pertinent information about the results of surgical specimen examinations of patients with bone tumors. These protocols are presented in the"Surgical Pathology Cancer Case Summary (Checklist)" that are essentials to pathologic reporting. Moreover, discussions of bone tumor evaluation, classification and biopsies, and cancer grading are also presented.

Context.--Smooth muscle tumors (SMTs) of the sinonasal tracts are very rare mesenchymal neoplasms, and the literature includes very limited data correlating histologic parameters with clinical outcome. As the behavior of SMTs is site-dependent, defining applicable criteria to distinguish among low-grade leiomyosarcoma, SMT of uncertain malignant potential (SMTUMP), and cellular leiomyoma is sometimes difficult and arbitrary. Objective.--To correlate the clinicopathologic features of 12 well-differentiated sinonasal SMTs with MIB-1 index and clinical outcomes so as to better classify this group of tumors. Design.--Twelve cases of sporadic well-differentiated SMTs arising from the sinonasal tract were retrieved from both institutions. High-grade leiomyosarcomas were excluded from this analysis. The histologic parameters assessed included circumscription, mucosal ulceration, cellularity, nuclear atypia, mitotic count, necrosis, and destruction of adjacent bony structures. The histologic classification of these tumors was based on the guidelines for SMTs of deep soft tissues, using greater than 4 mitotic figures (MF)/10 high-power fields (HPF) to separate SMTUMP from leiomyosarcoma and the presence of 1 to 4 MF/10 HPF to distinguish between leiomyoma and SMTUMP. Immunostaining of MIB-1 index was performed in 7 cases with available material. Results.---This study showed a 1:1.5 male-female ratio and a mean age of 40 years (range, 20-67 years). The most frequent symptoms were nasal stuffiness and/or epistaxis. The tumors involved nasal cavity in 8 cases (67%), paranasal sinus alone in 2 cases (16.5%), and both nasal cavity and paranasal sinuses in 2 cases (16.5%). The tumors ranged in size from 0.3 to 5.5 cm (mean, 2 cm) and were classified as follows: 7 leiomyomas, 2 SMTUMPs, and 3 low-grade leiomyosarcomas. All 7 leiomyomas, 1 SMTUMP, and 1 leiomyosarcoma originated from vessel walls. Bone involvement was seen in both the SMTUMPs (1 of 2) and leiomyosarcomas (2 of... [ABSTRACT FROM AUTHOR]

Follicular dendritic cell sarcoma of the liver is an uncommon pathologic entity, and only 5 cases have been reported previously. Herein, we report the first case, to our knowledge, of hepatic follicular dendritic cell sarcoma without evidence of Epstein-Barr virus infection. The patient is an elderly man who was found to have an incidental liver mass and then developed weight loss and fever. The diagnosis was based on the typical morphologic appearance of spindle cell proliferation associated with a brisk lymphoplasmacytic infiltrate and strong immunoreactivity to CD21 and CD35. Based on our experience and a review of the published reports, we summarize the clinical and pathologic features of hepatic follicular dendritic cell sarcoma and its surgical management. [ABSTRACT FROM AUTHOR]