A 50-year-old man developed recurrent swelling in the left popleteal region. Five months earlier a tumor was excised from the site, but pathology was not available. He had multiple cutaneous nodules of varying sizes increasing in size and number since his teens. In addition to the large spongy mass in the left popliteal fossa, he had multiple disseminated cafe-au-lait macules. His hearing was normal. Excision of the patient’s popliteal tumor revealed a malignant peripheral nerve sheath tumor.His father and both
brothers had similar swellings. His 18-year-old son began to develop cutaneous nodules at the age of 15years.
Panel-A shows multiple neurofibromas and cafe-au-lait spots. Panel-B shows recurrent popliteal tumor with old surgical scar. Panel-C shows the cut surface of the tumor exhibiting fist flesh appearance and areas of hemorrhages. Panel-D shows spindle cells with vesicular nucleus, prominent nucleoli and abnormal mitotic figure (Arrow head).