Clear cell sarcoma arising in the retroperitoneum

Primary Clear Cell Sarcoma of the Ileum: A Case Report With Next-Generation Sequencing Analysis

As the concept of clear cell sarcoma-like tumor or malignant gastrointestinal neuroectodermal tumor (CCS-LT/MGNET) has been widely accepted, primary CCS of the gastrointestinal tract (CCS-GI) is becoming a rare entity. In this article, we describe a case of primary CCS-GI that occurred in the ileum of a 65-year-old male to further illustrate its rare occurrence. Similar to CCS of soft tissue (CCS-ST), the tumor was composed of spindled to epithelioid cells displaying fascicular, nested, or pseudopapillary arrangement. The tumor cells had large round to ovoid nuclei with vesicular chromatin and prominent nucleoli, containing eosinophilic to pale cytoplasm. In contrast to CCS-LT/MGNET, immunohistochemical study also showed variable positivity of HMB45, melan A, and MiTF besides the strong and diffuse staining of S100 protein and SOX10. Fluorescence in situ hybridization (FISH) using fusion probes identified EWSR1 and ATF1 genes rearrangement. Next-generation sequencing (NGS) analysis further revealed EWSR1 exons9/8-ATF1 exon4 and ATF1 exon3- EWSR1 exon11 fusion genes. CCS-GI and CCS-LT/MGNET possibly represent 2 related entities of the same spectrum, which differentiate along 2 different pathways.

Retroperitoneal Sarcomas: An Update on the Diagnostic Pathology Approach

Retroperitoneal sarcomas are a heterogenous group of rare tumors arising in the retroperitoneum. Retroperitoneal sarcomas comprise approximately 10% of all soft tissue sarcomas. Though any soft tissue sarcoma histologic types may arise in the retroperitoneal space, liposarcoma (especially well-differentiated and dedifferentiated types) and leiomyosarcoma do so most commonly. Retroperitoneal sarcomas are diagnostically challenging, owing to their diversity and morphological overlap with other tumors arising in the retroperitoneum. An accurate diagnosis is necessary for correct management and prognostication. Herein, we provide an update on the diagnostic approach to retroperitoneal sarcomas and review their key histologic findings and differential diagnoses.

Clear cell sarcoma of the soft parts arising in the rectus abdominis in a child - aspiration cytology of a rare case

BACKGROUND

Clear cell sarcoma of soft parts is most commonly found associated with the tendons and aponeuroses of distal extremities in young adults with a peak incidence in the third decade. Location in the abdominal wall and in a child is very rare.

CASE PRESENTATION

A nine-year-old female child presented with a swelling in the anterior abdominal wall in the suprapubic region. Fine needle aspiration revealed predominantly discrete cells with loose clustering at places. The cytoplasm was abundant, finely granular, and eosinophilic with some cells exhibiting clear vacuolated zones. No pigment was seen. The nuclei were rounded and eccentrically placed with a striking single eosinophilic macro nucleolus present in all the cells. Taking into consideration, the history, age of the patient, location of the tumor and absence of melanin pigment, a diagnosis of soft tissue sarcoma was made, the differential including Clear cell sarcoma. This was subsequently confirmed on histopathological examination and immunohistochemistry

CONCLUSION

The atypical presentation of the case made the cytological diagnosis rather challenging. Clear cell sarcoma should be considered when cytology of a soft-tissue tumor shows uncharacteristically high cellularity and relatively uniform cells with macronucleoli.