A case of Langerhans cell histiocytosis following acute basophilic leukemia

Abstract

Dear Editor, Langerhans cell histiocytosis (LCH) is a class of histiocytic cell neoplasm with a clonal neoplastic proliferation of Langerhans-type cells that express CD1a, langerin, and S100 protein and show evidence of Birbeck granules by ultrastructural examination [1]. Concurrent LCH and malignancy have been reported occasionally. LCH occurred before or after malignancies including acute lymphoblastic leukemia, acute myeloid leukemia, and several solid tumors such as malignant lymphoma, retinoblastoma, lung carcinoma, ependymoma, hepatocellular carcinoma, Askin tumor, etc. [2–5]. We present the case of a 38-year-old patient who was diagnosed with LCH following acute basophilic leukemia (ABL). A 38-year-old male presented to the emergency department with a 2-month history of indigestion, nausea, and easy fatigue. Complete blood count with differential showed a white blood cell count of 13,500/μL with 13 % blasts and 14 % basophils, 8.4 g/dL hemoglobin, and a platelet count of 110,000/μL. Hepatosplenomegaly and multiple lymphadenopathies were noted. Bone marrow (BM) aspirates showed 15.6 % leukemic blasts and 11.6 % basophils. Since marked dilution of BM aspirate specimens, the proportion of blasts and basophiles were inaccurate. However, the BM cellularity was approximately 100 % with leukemic blasts. The blasts were of medium-to-large size, had round or cleaved nuclei, contained one or two nucleoli, and a had small amount of bluish cytoplasm. Some blasts had basophilic granules (Fig. 1). Flow cytometric analysis confirmed the presence of the surface markers CD34, CD13, CD33, CD117, and CD65. The blasts showed negative reaction for myeloperoxidase, periodic acid stain, and nonspecific esterase but metachromatic positivity after staining with toluidine blue. Electron microscopy confirmed the presence of basophilic granules in blasts (Fig. 1). The karyotype analysis demonstrated trisomy 16 (47,XY,+16[3]/46,XY[17]). The patient was diagnosed with ABL and received induction chemotherapy. Three months after induction chemotherapy, multiple erythematous indurated patches were observed on the left lower abdomen. Skin biopsy showed evidence of diffuse neutrophilic infiltration with papillary dermal edema and eczematous lesions, without evidence of cancer or fungal infection. Follow-up of BM studies revealed a normocellular marrow with 4.0 % blasts. However, marked increase of histiocytic cells, including immature forms, was noted. The histiocytic cells were clustered in a nodular pattern on the BM clot section. They were of medium-to-large size, with grooved or lobulated nuclei, inconspicuous nucleoli, and moderate amount of homogeneous pinkish cytoplasm. The histiocytic cells were positive for CD1a, S100, and CD68 marker proteins by immunohistochemistry staining (Fig. 2). Based on the morphology and immunohistochemical staining profiles, the patient was diagnosed with BM involvement of LCH. However, a primary lesion of LCH was not found. The patient underwent haploidentical BM transplantation; however, his clinical course continued to deteriorate with systemic fungal infection, necrotizing pneumonia, and hemodynamic instability. Despite aggressive treatment, the patient expired 7 months after diagnosis of ABL. T.-D. Jeong : S. Jang (*) :C.-J. Park :H.-S. Chi Department of Laboratory Medicine, College of Medicine, University of Ulsan and Asan Medical Center, 88, Olympic-ro 43-gil, Songpa-gu, Seoul 138-736, South Korea e-mail: ssjang@amc.seoul.kr