Flow cytometric analysis of DNA ploidy in childhood rhabdomyosarcoma

Myofibrosarcoma of the nasal bone

Myofibrosarcoma is a recently recognized rare tumor that mainly occurs in adults. These tumors are composed of a collagenous stroma and pleomorphic stellate to spindle-shaped cells that resemble smooth muscle cells with eosinophilic cytoplasm and tapered nuclei. We present a case of myofibrosarcoma of the nasal bones in a 4-year-old girl who showed rapid enlargement of a painless glabellar swelling. Computed tomography and magnetic resonance imaging revealed an expanding solid mass with erosion of the surrounding nasal bones. After excision and histopathological examination, this tumor was identified as a myofibrosarcoma. This is the first report of such a tumor localized to the glabellar region. This case report contributes to better awareness of an extremely rare type of glabellar lesion in children.

Pathologic classification of rhabdomyosarcomas and correlations with molecular studies

Rhabdomyosarcoma, the most common soft-tissue malignancy of childhood and adolescence, comprises a group of differing pathobiologic entities linked by their common propensity for formation of neoplastic skeletal muscle, a feature that results from biological forces related to aberrant transcription signals and the resultant production of myogenic proteins. At a molecular level, however, rhabdomyosarcomas form a heterogeneous group that can be subdivided into distinct clinicopathologic entities based on morphologic appearance and genetic makeup. These differing morphologic features were recognized in the mid-1900s by Horn and Enterline with their division of rhabdomyosarcomas into embryonal, alveolar, botryoid, and pleomorphic subtypes. More recent histologic and biologic studies have resulted in description of additional entities, such as spindle cell and anaplastic rhabdomyosarcoma, and refinements in recognition of the original entities, such as solid-alveolar rhabdomyosarcoma. Familiarity with newer classifications and their relationship to molecular aberrations is key to stratifying patients on current therapeutic protocols and proposed innovative genetic therapies.