New York Association of Neuropathologists
Presented by: Dr. Zeng - Kings County Hospital
Case to be distributed as a PowerPoint presentation by e-mail): A 65 year old woman reported gradual leg pain and swelling of the right lower leg for the past nine months. A 10 x 9.4 cm mass was found in the posterior aspect of right lower leg on CT scan and MRI with involvement of the fibula. The patient was diagnosed with leiomyosarcoma of the uterus in 1983, and she had hysterectomy, radiation therapy and chemotherapy. She was found to have a recurrence with a 9 cm pelvic mass in 2005. At that time she was not deemed to be a candidate for resection. She was followed up with serial CT scans showing very slow growth of the pelvic tumor.
A needle biopsy of the leg mass was performed.
Sections showed a pleomorphic neoplasm of spindly to rounded cells with pink cytoplasm and possible strap cells. Mitotic activity was easy to find. The tumor was positive for HF35 (muscle specific actin) especially in the large rounded cells. Desmin was positive in a few of the large cells. A few large cells were positive for myoglobin and myogenin stained scattered nuclei. The tumor was negative for AE1/3, SMA, HMB45, S100 and calponin but positive with vimentin.
The diagnosis was pleomorphic rhabdomyosarcoma.
The tumor was compared to the pelvic mass and the uterine mass. Both were spindle cell tumors with some pleomorphism and mitotic activity. They were positive for SMA and calponin but negative for myoglobin and myogenin.
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