Complete mimicry: a case of alveolar rhabdomyosarcoma masquerading as acute leukemia

Abstract

BackgroundA small number of rhabdomyosarcoma (RMS) cases involve the bone marrow. A leukemic presentation of RMS has been reported in a few case series, although almost all cases of leukemic RMS are not completely mimicking leukemia. We encountered a case with RMS cell infiltration of the bone marrow that resembled floating hematological cells.Case presentationWe encountered a rare case of a 15-year-old boy with a 2-week history of left femoral pain. Upon admission, he was afebrile with no other symptoms. No apparent cause of femoral pain was detected on an initial examination. Laboratory findings revealed normal white blood cell (WBC) count and hemoglobin concentration, with a platelet count of 10.3 × 104/μL. WBCs included 2.0% metamyelocytes, 4.5% myelocytes, and 0.5% blasts. Lactate dehydrogenase concentration was 1299 U/L, creatine kinase was 437 U/L, and C-reactive protein was 1.25 mg/dL. Bone marrow aspiration demonstrated hypercellular marrow (nucleated cell count 1.84 × 104/μL) and 89.0% of blast-like cells of all nucleated cells. The proliferating cells were negative for myeloperoxidase and esterase, and strongly positive for CD56. Positron emission tomography exhibited extensive accumulation of 18F–fludeoxyglucose with a SUVmax of 7.09. Magnetic resonance imaging revealed T1-low intensity, gadolinium-enhanced, diffuse, and irregular lesions on his pelvis and bilateral femurs. These laboratory and imaging findings suggested hematological malignancy with diffuse bone involvement, suggestive of acute leukemia. However, the pathological diagnosis of bone marrow and basal penile muscle biopsy was alveolar RMS. Karyotype analysis of bone marrow cells revealed the characteristic translocation of t(2;13)(q35;q14). The final diagnosis was alveolar RMS with massive involvement of the bone marrow and the primary site in the perineal muscles. The tumor cells both of the primary site and bone marrow were positive for myogenin.ConclusionsA literature review found a misdiagnosed case of completely mimicking leukemic RMS as natural-killer (NK)-cell leukemia. Such a misdiagnosis can have critical consequences. We experienced a rare case of alveolar RMS with symmetrical diffuse bone marrow involvement completely masquerading as acute leukemia. The results of a surface marker study showing that the tumor cells had a near NK-cell phenotype were misleading.

Vacuolated Blasts in the Bone Marrow of A Child with Rhabdomyosarcoma

“…Burkitt's lymphoma with marrow involvement, especially if there are prominent vacuolizations, as in our case [1,2]. In the literature, all patients presenting with bone marrow involvement were diagnosed with alveolar type RMS [3].…”

“…The most common locations are the head/ neck region and genitourinary tract. Leukemic presentation of RMS with diffuse bone marrow involvement and unknown primary mass is very rare [1]. Most of the time it can be misdiagnosed as acute leukemia.…”

Rhabdomyosarcoma debut masquerading as acute lymphoblastic leukemia: A case report and review of the literature

“…Bone marrow infiltration by ARMS is uncommon; some cases can mimic acute leukemia at presentation and thus mislead the diagnosis. We conducted a PubMed search of similar cases of ARMS with a leukemic presentation, finding 41 cases of mimicry reported in the literature, the oldest reported four decades ago . We added our case and reviewed the data available from these reports on Table .…”

“…We conducted a PubMed search of similar cases of ARMS with a leukemic presentation, finding 41 cases of mimicry reported in the literature, the oldest reported four decades ago. [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] We added our case and reviewed the data available from these reports on Table 1.…”

Alveolar rhabdomyosarcoma mimicking acute leukemia in an adolescent with deep venous thrombosis – case presentation

“…There were no specific clinical criteria for acute leukemia, the bone marrow aspirate was the one who pleaded for acute leukemia. All these studies have shown that the bone marrow infiltration is uncommon, but when it appears can lead to misdiagnosis, delaying or even losing the diagnosis (17)(18)(19)(20).…”