A 50-year-old man presented with a solitary, slow growing mass in the left calf region since two years. The patient gave history of rapid increase in size of the swelling since two months following thorn injury. Magnetic Resonance Imaging (MRI) revealed a large well defined lobulating heterogenous soft tissue malignant neoplasm arising from posteromedial aspect of gastrocnemius muscle extending into subcutaneous plane. Fine Needle Aspiration Cytology (FNAC) of the swelling revealed a low cellular smear with bland spindle shaped cells having moderate amount of cytoplasm, elongated nuclei and inconspicuous nucleoli admixed with anastomosing capillary network and few mature adipocytes in a haemorrhagic background. Based on these findings differential diagnosis of haemangioma or angiolipoma were given.Wide surgical excision of the mass was done and sent for histopathological evaluation. Grossly, the mass measured 13.5 x 12 x 6 cm with an ulcer on the skin surface measuring 6 x 5 cm. On cut surface, circumscribed, firm mass was noted measuring 9 x 5.5 cm, which was predominantly solid having lobulated appearance. Also, seen many blood filled cystic spaces of varying sizes [Table/ Fig-1,2].Microscopically, the lesion was unencapsulated with vascular and cellular areas. Cellularity was variable and it was composed of hyper and hypocellular areas. The tumour tissue in the hyper cellular areas predominantly comprised of spindle shaped cells arranged in interlacing bundles and fascicles, with round to oval vesicular nuclei, inconspicuous nucleoli and moderate amount of eosinophilic cytoplasm. Few pleomorphic cells having vesicular single or multilobated nucleus with prominent nucleoli and abundant eosinophilic cytoplasm were also noted. Few cells showed intranuclear inclusions. Many multinucleated giant cells were also noted. Hypocellular areas were comprised of spindle shaped cells with round to oval nuclei having fine nuclear chromatin and moderate amount of eosinophilic cytoplasm and were dispersed in a myxoid background. These tumour cells were infiltrating the adjacent adipose tissue focally. The vascular areas were comprised of many, large clusters of ectatic thin walled blood vessels. Subendothelial fibrin deposition, organized luminal thrombus and perivascular hyalinization were noted in majority of the vessels. AbStRACtPleomorphic Hyalinizing Angiectatic Tumour (PHAT) is one of the rare soft tissue tumour which is non-metastasizing. The origin of this tumour is yet uncertain. It occurs in adults as a slow growing subcutaneous mass mimicking clinically and histologically to various benign and malignant soft tissue tumours such as schwannoma, haemangioma and malignant fibrous histiocytoma. The microscopic features of this tumour include clusters of ectatic, fibrin containing, hyalinized blood vessels with pleomorphic and spindle shaped tumour cells showing intranuclear inclusions, stromal haemosiderin pigment and a variable inflammatory infiltrate. Despite marked pleomorphism, the lesion behaves as a low grade neo...

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