Case Report MEDICINE AND PHARMACY REPORTS Diagnostic dilemma in soft tissue swelling over fnger Ruchi Nagpal 1 , Arvind Ahuja 2 1) Department of Pathology, Bhaskar Medical College & General Hospital, Hyderabad, India 2) Department of Pathology, PGIMER, Dr Ram Manohar Lohia Hospital, New Delhi, India Abstract Myopericytoma is a benign tumor that shows a pericytic line of diferentiation. The lesion is generally located in the dermis and subcutaneous tissue and has a predilection for distal extremities, but may be found in any part of the body. We present a case of 48-year old male who came with painful swelling in right middle fnger for the past 2 years. Histopathology showed proliferation of spindle-shaped cells exhibiting a hemangio-pericytomatous pattern with various sized vessels lined by fattened endothelium and surrounded by a concentric arrangement of spindle-shaped cells. Tumor cells showed membranous positivity for smooth muscle actin but negative for desmin and CD 34. Hence diagnosis of intravenous myopericytoma was established. Keywords: myopericytoma, intravenous, actin, CD34 Case report Myopericytoma (MP) is a benign tumor that shows diferentiation towards pericytes [1]. The lesion is generally located in the dermis and subcutaneous tissue and has a predilection for distal extremities, but it may be found in any part of the body [2]. It is composed of oval to spindle-shaped myoid-appearing cells with a strong tendency towards concentric perivascular growth [2,3]. An intravascular myopericytoma (IVMP) is a distinct, histological variant [1] and has been rarely documented. A 48-year-old male presented with painful swelling in left middle fnger for the past 2 years. There was no history of trauma or previous injury. On examination, there was palpable subcutaneous lump measuring 0.5 cm in diameter on the volar aspect of left middle fnger and was clinically diagnosed as ganglion cyst. Radiograph showed soft tissue swelling over the middle fnger (Figure 1). The resected specimen (0.8 X 0.5 cm) sent for histological examination revealed a solid tumor that had replaced part of the vessel wall and completely flled the lumen (Figure 2a). The tumor showed proliferation of spindle- shaped cells exhibiting a ‘‘hemangio- pericytomatous’’ pattern (Figure 2b). The presence of various sized vessels with fattened endothelium surrounded by a concentric arrangement of rounded or slightly spindle-shaped cells was evident (Figure 2c). The lesional spindle cells were arranged in sheets in the intervascular areas. Few thick walled vessels with plump endothelial cells were also noted. No atypia, mitosis or necrosis were observed. Immunohistochemistry: tumor cells showed membranous staining for smooth muscle actin (SMA) (Figure 3a) but negative for desmin (Figure 3b) and CD 34 (Figure 3c). The muscular wall of the vessel within which tumor was located showed cytoplasmic positivity for desmin (Figure 3b). Based on the above fndings diagnosis of intravascular myopericytoma was established. Address for correspondence: ruchi2001@gmail.com Manuscript received: 30.05.2019 Received in revised form: 29.07.2019 Accepted: 02.08.2019 DOI: 10.15386/mpr-1377