Systemic rhabdomyosarcoma presenting as leukemia: Case report with ultrastructural study and reviews

Abstract

A 20-year-old white male was initially suspected clinically and pathologically of having an acute lymphoblastic leukemic process because of fatigue, severe anemia, thrombocytopenia, a leuko-erythroblastic peripheral blood picture, and a diffusely infiltrated bone marrow. Subsequent review of the bone marrow material indicated cytologic features consistent with either an embryonal, undifferentiated small cell mesenchymal malignancy or reticulo-endothelial malignancy. Ultimately, the electron microscopic (EM) study of the tumor proved to be diagnostic of rhabdomyosarcoma. An extensive search for a primary site of rhabdomyosarcoma did not show any lesion, although the genitourinary region was clinically suspected. The clinical course was a rapidly downhill one with extensive bone and CNS involvement. The patient died 5 months later. An autopsy permit was not obtained. This case emphasizes the occasional tendency of rhabdomyosarcoma to masquerade as a hematopoietic malignancy at the time of presentation and the usefulness of EM study in confirming a diagnosis.

Massive bone marrow involvement by clear cell variant of rhabdomyosarcoma

“…Multinucleated tumor cells and the tumor cells with hemophagocytic activity were also noted. [3][4][5][6][7][8][9] This cytologic spectrum has been documented with both alveolar and embryonal subtypes of RMS and therefore has no reference to the histologic variants. Cytomorphologically, our case bore a striking resemblance to those previously reported.…”

“…Cytomorphologically, our case bore a striking resemblance to those previously reported. [3][4][5][6][7][8][9] Primary RMS, especially the alveolar subtype, is often recapitulated histologically by its metastases, including those seen in BM biopsy. 3, 10, 11 Reinecke, et al (1998) reported a case, in which the BM biopsy displayed an extensive tumorous infiltrate with the alveolar spaces lined by primitive round cells.…”

“…1,2,3 The primary tumors are frequently found in the head and neck or genitourinary tract, but rare cases of BM metastases with an unknown primary site have been reported. [4][5][6][7][8][9][10][11] RMS comprises various histologic variants, with embryonal and alveolar subtypes being the most common. 12 Alveolar RMS is associated with a poorer prognosis and cytogenetically identified by either of two chromosomal translocations t(2;13) or t(1;13).…”

Hematologic masquerade of rhabdomyosarcoma

“…In many of the reports, much emphasis has been placed on immunohistochemistry and/or electron microscopic examination as differential diagnostic approaches in cases of RMS with bone marrow involvement [4,[6][7][8][9]11,15,32,41]. As far as immunochemistry is concerned, the absence of the most common lymphocyte markers could be considered a possible consequence of dedifferentiation of the cells, therefore not excluding a highgrade lymphoma or acute leukemia [26].…”

Alveolar rhabdomyosarcoma mimicking lymphoma with bone marrow involvement

“…Alveolar rhabdomyosarcoma are small, blue, round-cell tumors requiring aggressive oncologic treatment. Depending on the location and stage, they can mimic other neoplasms, thus making the diagnostic process challenging [4,5,7].…”