Histiocytic sarcoma (HS) is a rare, non-Langerhan's, malignant histiocytic neoplasm that occurs in lymph nodes and extranodal sites mainly the skin and intestine. Amidst the cases reported so far; majority of the cases previously diagnosed as HS have been Primary T cell lymphomas (PTCL). Cases primarily involving the extranodal sites are rare, with a confusing clinical picture and thus, are often misdiagnosed. Here we report a rare case of extranodal HS in a 54-year-old man, a previously treated case of gastrointestinal stromal tumor (GIST) of the stomach, who now presented with abdominal pain. On imaging, a growth was detected in the small bowel without accompanying lymphadenopathy.

Carcinosarcomas, also known as malignant mixed Müllerian tumours (MMMT), are aggressive neoplasms that are biphasic as they contain both carcinomatous and sarcomatous elements. Most commonly arising from the endometrium, extragenital carcinosarcomas are extremely rare and most cases develop from the peritoneum. The case is reported of a 70-year-old female who presented with abdominal pain and distention. On evaluation a large abdomino-pelvic mass with ascites was noted. She underwent complete cytoreductive surgery and the histopathology reported carcinosarcoma of primary peritoneal origin, of heterologous type arising de novo from the secondary Müllerian system with no synchronous or metachronous carcinomas or endometriosis. She declined adjuvant treatment and represented with disseminated abdominal disease and unfortunately succumbed to the disease within four months. Carcinosarcomas of the extragenital sites have been postulated to arise from pre-existing foci of endometriosis, Müllerian duct remnants, or the secondary Müllerian system, all of which are derivatives of the coelomic epithelium. They are extremely aggressive, and there is little knowledge concerning their natural history and scant data regarding their management.

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Mitotically active cellular fibroma (MACF) is a category of fibromatous tumours of the ovary described in the WHO classification of tumours of female reproductive organs. The case of a 54-year-old female who presented with lower limb swelling due to deep vein thrombosis (DVT) is reported. On examination, she had a 5 × 8 cm fixed pelvic mass. She underwent optimal cytoreductive surgery. Grossly the tumour, which was found to occupy the left pelvic space, was hard and irregular in shape and was adherent to the surrounding structures. Histopathology revealed collagen-producing spindle cells showing mitotic activity of 6-8/10 HPF with minimal nuclear atypia and Ki 67 labelling index of 10%. A final diagnosis of MACF was made. In view of sparse evidence regarding its management and due to residual tumour (< 1 cm), she received adjuvant radiotherapy. She has remained disease free over a period of two years.

SATB2 is a nuclear protein that plays a critical role in osteoblast lineage commitment. Diagnosing extra skeletal osteosarcomas at rare sites can be quite challenging as it might mimic hyalinized stroma. The utility of SATB2 expression in osteosarcomas and other bone and soft tissue tumours is an useful adjunct to histopathology in diagnosing these rare lesions. A 69 year old male, presented with scrotal swelling since 8 months. He underwent left sided orchidectomy because of the clinical suspicion of malignancy. Macroscopy revealed a solid mass in the para testicular tissue with no involvement of the testicular tissue. Cut surface is whitish, firm and homogenous. Microscopy showed malignant soft tissue tumor with areas showing osteoid differentiation and SAT B2 helped in confirmation of diagnosis by highlighting the osteoblastic nature of cells. Hence a diagnosis of Primary extra skeletal paratesticular osteosarcomas was made.