Severe rhabdomyolysis developing in an advanced melanoma patient treated by pembrolizumab followed by dabrafenib trametinib combined therapy

Abstract

massive nodule with a thin grenz zone extending from the dermis to the subcutis (Fig. 1c). Neoplastic cells were uniform, atypical, medium-sized lymphoblasts with round or convoluted nuclei, scant cytoplasm, condensed nuclear chromatin and indistinct nucleoli (Fig. 1d). Macrophages were scattered, resembling a starry-sky pattern (Fig. 1d). Neoplastic cells were positive for CD79a and terminal deoxynucleotidyl transferase (TdT) expression, and were negative for CD3, CD20, CD30, CD34, CD45RO, CD99, c-kit, cytokeratin, neuron-specific enolase and S100 protein expression. Laboratory findings revealed a high level of soluble interleukin-2 receptor (sIL-2R) (1220 U/mL; normal, 121–613). Atypical lymphoblasts that were positive for CD19 and CD22 expression accounted for 67% of the bone marrow infiltrate. Although t(5;16)(p15;q15) was observed, KMT2A rearrangement was not detected. F-fluorodeoxyglucose (FDG)positron emission tomography/computed tomography (PET/CT) revealed no other masses. Administration of multiagent systemic chemotherapy resulted in a complete remission, with disappearance of the chromosomal abnormality, as detected by re-biopsy of the bone marrow. Case 2 was of B-LBL in a 9-month-old female infant who presented with a rapidly growing, elastic-hard, dark-red nodule, measuring 18 mm 9 18 mm on the right root of the nose (Fig. 1e). Dermoscopy showed linear-irregular or arborizing vessels. Histological findings were nearly the same as case 1. The neoplastic cells were positive for CD7, CD79a, PAX5 and TdT (Fig. 1f) expression, and were negative for CD1a, CD3, CD20, CD30, CD34, CD45RO, CD99, c-kit, AE1/AE3 and Epstein–Barr virus-encoded small RNA expression. Slight elevation of liver enzyme levels was detected (asparagine aminotransferase, 94 U/L; alanine aminotransferase, 41 U/L). Atypical lymphoblasts that were positive for CD19, CD22 and CD59 expression accounted for 10.2% of the bone marrow infiltrate. No chromosomal abnormalities were detected. FDG-PET/CT revealed no other masses. Multiagent systemic chemotherapy was initiated, followed by a rapid response. B-cell ALL/LBL occasionally shows as single or multiple, erythematous to blue, firm papules and nodules, potentially with overlying telangiectasias on the head and neck areas in children. In both of the present cases, solitary nodules rapidly grew on the face of infants. Although solitary nodules in infants are reminiscent of mastocytoma, Langerhans cell histiocytoma and lymphoma, the rapid growth and dermoscopic telangiectasias may suggest lymphoma. Due to good response to treatment, it is essential that B-ALL/LBL is diagnosed early and accurately. In summary, we have described two cases of B-ALL/LBL with solitary cutaneous nodules on the face in infants.