Soft tissue tumors constitute a heterogeneous and large group of neoplasm and always have fascinated clinicians and pathologists for many years. Adipose tumors formed single most common histological group in soft tissue tumors and liposarcoma constitute 20% of all malignant mesenchymal tumors. Atypical lipomatous tumor/Well-differentiated liposarcoma (ALT/WDLPS) forms a rare adipose tissue malignant neoplasm. This is a case of a 31-year-old female, presented in surgical op with complaints of painless mass in the left thigh. Physical examination revealed a nodular swelling in the superficial soft tissue of the left thigh m/s 9x8cm and a pre operative diagnosis of lipoma was made. The mass was removed surgically and the microscopic sections showed a cellular adipocytic neoplasm arranged in lobules separated by fibrous strands. The fibrous septae show atypical cells with irregular hyperchromatic indented nucleus and cytoplasm showing multiple small vacuoles. Since the tumor was located in the superficial soft tissues, a diagnosis of atypical lipomatous tumor/Well-differentiated liposarcoma with low chance for recurrence was made and patient was referred to higher centre for further management.
