Primary embryonal rhabdomyosarcoma of the ovary in a 4-year-old girl

Embryonal Rhabdomyosarcoma of the Ovary and Fallopian Tube: Rare Neoplasms Associated With Germline and Somatic DICER1 Mutations

DICER1 mutations (somatic or germline) are associated with a variety of uncommon neoplasms including cervical and genitourinary embryonal rhabdomyosarcoma (ERMS). We report a primary ovarian and 2 primary fallopian tube ERMS occurring in 60-, 13-, and 14-year-olds, respectively. The 3 neoplasms exhibited a similar morphologic appearance being polypoid and containing edematous hypocellular areas and hypercellular foci composed of small cells with scant cytoplasm exhibiting rhabdomyoblastic differentiation (desmin, myogenin, myoD1 positive). There was cellular cartilage in all cases and extensive foci of anaplasia, eosinophilic globules, and bone/osteoid in 1 case each. All 3 neoplasms exhibited DICER1 mutations; in 1 of the tubal cases, the patient had a germline mutation and in the other 2 cases, the DICER1 mutations were somatic. Accompanying DICER1 "second hits" were identified in all cases. In 2 of the neoplasms, SALL4-positive glandular structures were present which we speculate may represent an unusual primitive "metaplastic" phenomenon. Our study adds to the literature on ERMS at unusual sites associated with DICER1 mutations. ERMS arising at such sites, especially when they contain cartilage or bone/osteoid, are especially likely to be associated with DICER1 mutations. Pathologists should be aware of this as these may be the sentinel neoplasms in patients with DICER1 syndrome and confirming a germline mutation can facilitate the screening of the individual and affected family members for other neoplasms which occur in this syndrome.

Primary ovarian rhabdomyosarcoma in a dog

A 10-year-old female English pointer was diagnosed with an ovarian tumour with abdominal metastases. Ultrasonography revealed several nodules of 1-5 cm diameter within the abdominal cavity. Fine needle aspiration cytology of the nodules suggested a malignant mesenchymal tumour. On necropsy examination the right ovary and its capsule were enlarged and there were white-red, friable nodular masses distributed over the surface of the pancreas, liver, omentum, mesentery and serosae of the small and large intestines. Microscopical evaluation revealed neoplastic cells with a high degree of pleomorphism and vascular invasion. Immunohistochemically, the neoplastic cells expressed myosin, desmin, vimentin and CD10, but were negative for cytokeratin, placental alkaline phosphatase, inhibin-alpha and smooth muscle actin. Based on these findings a diagnosis of primary ovarian alveolar rhabdomyosarcoma was made.

Primary ovarian rhabdomyosarcoma in children

Although rhabdomyosarcoma (RMS) is the most common soft tissue sarcoma in children, primary rhabdomyosarcomas of the ovary are extremely rare, with only eight well-documented pediatric cases previously reported in the literature. We present two additional cases: an alveolar RMS originating in the right ovary with metastatic spread to the splenic flexure of the colon and to both lungs in a 13-year-old African American girl, and an embryonal RMS arising in the right ovary of a 6-year-old Caucasian girl with pre-operative intra-abdominal rupture and a malignant right pleural effusion. Both patients had complete resection of their primary tumors and received chemotherapy including vincristine, doxorubicin and cyclophosphamide with good response to therapy. Both are alive 8 and 9 months post-operatively.

Genitourinary rhabdomyosarcoma. Treatment options

Dramatic improvements have occurred in the treatment and prognosis of the child with rhabdomyosarcoma over the past 2 decades. Increased understanding of tumor behavior has improved survival and focused attention on important quality of life issues. Future therapeutic advances will depend largely on an improved molecular understanding of altered cell behavior and the continued efforts of multi-institutional studies.