2017 Resarch Forum

IM: C-9

Applicant & Principal Investigator: Samiollah Gholam MD

Extraosseous Ewing’s Sarcoma presenting as a scrotal mass Samiollah Gholam MD, A Scott Ragland DO

INTRODUCTION: Ewing’s sarcoma is a highly malignant, poorly differentiated bone tumor of childhood and adolescence primarily involving diaphysis of long bones; femur, tibia, fibula, and humerus and may also occur in other bony structures and cartilage tissue. It is a very clinically aggressive tumor with high rates of recurrence and distant metastasis. Ewing’s Sarcoma (ES) is the second most malignant bone tumor after osteosarcoma, with the highest incidence in the second decade of life. ES has two forms: more common the osseous form and relatively rare extraosseous form (EES). EES has been reported in various tissues including chest wall, larynx, kidney, esophagus and spinal epidural. Per our knowledge and review of literature, in the following case, we report the first case of ESS presenting as perineal mass. PURPOSE: Rare Case Presentation – first of its kind, has not been reported in literature before. DISCUSSION: 18-year-old Hispanic Male presented to our facility with complaint of testicular swelling of 6 months’ duration with no associated dysuria, hematuria and no history of trauma. The swelling had been progressive with episodic lower back pain. CT abdomen and pelvis with contrast was remarkable for a large heterogeneous mass at the base of the penis with possible extension into the right scrotal sac; destructive lesion involving medial left iliac bone, L2 and T11 suggesting metastasis. This was followed by scrotal U/S which confirmed no involvement of the testis. MRI lumbar spine and pelvis confirmed the lesions at L2 and left medial iliac bone. CT chest was significant for multiple pulmonary nodules of varying sizes and multiple lytic lesions in the thoracic vertebra. Otherwise he had a normal CBC with diff, BMP, LFT and UA. He underwent biopsy by Urology and Interventional Radiology, and both results were positive for ESS. Lab: Cytokeratin AE1/AE3 = Negative. EMA = Negative. Desmin = Negative. CD99 = Positive with strong membrane expression. WT1 = Negative. CA-125 = Negative.

CD45 = Negative. CD57 = Negative. S-100 = Negative. MyoD1 = Negative. FLI-1 = Positive.

This is the first case of ESS manifesting at scrotal mass based on the literature review. As compared to ES, ESS is aggressive with common site of metastasis being the lumbar vertebra and lungs, which was seen in this patient with 5-year survival ranging from 33 to 48%. It is important to keep ESS in differential diagnosis in a young patient with soft tissue mass regardless of the location, a biopsy is warranted. CONCLUSION: ESS can manifest in different tissues; this case demonstrates the first case of ESS as a perineal mass.