A Rare Lesion of Soft Tissue Malakoplakia Mimicking Neoplasm in the Thigh.

Malakoplakia, a rare acquired histiocytic inflammatory disease. It is an incidental finding on histopathology examination, as it does not have definite clinical manifestations. It typically affects the genitourinary tract but can also involve various anatomical sites. We present malakoplakia involving the left thigh, a rare extragenital manifestation. A 42-year-old male patient presented with insidious left thigh swelling, which gradually increased in size over a year, without associated pain or systemic symptoms. Imaging and fine needle aspiration cytology prompted a suspicion of malignancy. Wide resection was performed, and histopathological examination revealed characteristic features of malakoplakia, including Michaelis-Gutmann bodies and histiocytic infiltrates. Immunohistochemistry confirmed the histiocytic origin of the cells. Despite the absence of microbiological correlation, the patient remained asymptomatic with no recurrence at one-year follow-up. Malakoplakia poses diagnostic challenges due to its non-specific clinical and radiological features. Comprehensive histopathological evaluation is essential for accurate diagnosis, particularly in atypical locations. Our report underscores the importance of considering malakoplakia in the differential diagnosis of soft tissue masses, highlighting the need for further research to elucidate its pathogenesis and optimize management strategies.