Yamada et al. Diagnostic Pathology 2012, 7:143 http://www.diagnosticpathology.org/content/7/1/143 CASE REPORT Open Access Primary splenic histiocytic sarcoma complicated with prolonged idiopathic thrombocytopenia and secondary bone marrow involvement: a unique surgical case presenting with splenomegaly but non-nodular lesions Sohsuke Yamada1*, Takashi Tasaki11, Naoko Satoh1,2, Atsunori Nabeshima1, Shohei Kitada1,3, Hirotsugu Noguchi1, Kozue Yamada4, Morishige Takeshita4 and Yasuyuki Sasaguri1 Abstract: A 67-year-old Japanese female was followed up due to prolonged idiopathic thrombocytopenia with non-response to steroid therapy for 4 years, but recent progressive pancytopenia, hypo-albuminemia, and hypo-γ-globulinemia were presented. An abdominal CT scan revealed heterogeneously enhanced splenomegaly without any nodular lesions. A splenectomy was performed, and gross examination showed markedly hyperemic red pulp, weighing 760 g, accompanied by multiple foci of peripheral anemic infarction. Surprisingly, microscopic findings exhibited a diffuse proliferation of medium-sized to large tumor cells having pleomorphic nuclei, prominent nucleoli, and abundant eosinophilic cytoplasm, predominantly within the sinuses and cords of the red pulp, which occasionally displayed conspicuous hemophagocytosis and vascular permeation. In immunohistochemistry, these atypical cells were specifically positive for CD68 (KP-1), CD163, and lysozyme, which was consistent with histiocytic sarcoma (HS) of the spleen. Subsequently, section from the aspiration of bone marrow showed infiltration of the neoplastic cells associated with erythrophagocytosis 2 months after the operation, but never before it. Therefore, primary splenic HS presenting with secondary bone marrow involvement was conclusively diagnosed. Since early diagnosis and treatment are necessary for the HS patients with poor outcomes, splenic HS should be considered as a differential diagnosis in cases with chronic thrombocytopenia and splenomegaly. Virtual slides: The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/ vs/1009474924812827 Keywords: Thrombocytopenia, Spleen, Splenomegaly, Histocytic sarcoma (HS), Hemophagocytosis Background node, or soft tissues [1-3], however, primary HS of the By definition, histiocytic sarcoma (HS), a rare spleen has been an exceedingly rare. Mathé G et al. first hematopoietic neoplasm, but a known entity, represent- proposed the term ‘HS’ tentatively in 1970 [4]. In con- ing as less than 0.5% of all non-Hodgkin’s lymphoma, is trast, since its description was strictly based on the malignant proliferation of cells presenting morphologic histologic similarities of the tumor cells to macrophages, and immunophenotypic characteristics of mature tissue this diagnostic challenge is further complicated as it is histiocytes [1,2]. HS is known to often present as loca- critical to clearly distinguish HS from other histiocytic lized disease confined to the intestinal tract, skin, lymph processes, from benign to malignant, such as hemopha- gocytic syndrome, malignant histiocytosis, and acute * Correspondence: [email protected] monocytic leukemia [5-7]. Despite that, the detailed 1Department of Pathology and Cell Biology, School of Medicine, University of evaluation of HS depends especially on the verification Occupational and Environmental Health, Kitakyushu 807-8555, Japan Full list of author information is available at the end of the article of histiocytic lineage and the exclusion of other © 2012 Yamada et al.; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Yamada et al. Diagnostic Pathology 2012, 7:143 Page 2 of 7 http://www.diagnosticpathology.org/content/7/1/143 malignancies, including anaplastic large cell lymphoma, immunohistochemical examinations. All immunohisto- diffuse large B-cell lymphoma, poorly differentiated car- chemical stainings were carried out using Dako Envision cinoma, malignant melanoma, follicular dendritic cell kit (Dako Cytomation Co., Glostrup, Denmark) accord- sarcoma, or interdigitating dendritic cell sarcoma, by ing to the manufacturer’s instructions, and using com- way of thorough immunohistochemical examination [1- mercially available prediluted monoclonal antibodies 3,8,9]. In this context, it is very difficult to interpret HS against the following antigens: CD1a (Immuno Tech. papers published more than 25 years ago, i.e., before the Co., Ltd., Osaka, Japan, diluted 1:2), CD3 (Dako, diluted development and widespread use of immunohistochem- 1:1), CD4 (Dako, diluted 1:1), CD5 (NOVOCASTRA la- ical techniques and the availability of molecular genetic boratories Ltd., Newcastle, United Kingdom, diluted tools [3]. Actually, until now, the number of ‘true’ cases 1:25), CD8 (Nichirei Biosciences Inc., Tokyo, Japan, reported as primary splenic HS in the English literatures diluted 1:1), CD10 (NOVOCASTRA, diluted 1:20), is only few, up to 7, and most recent references are from CD20 (Dako, diluted 1:200), CD21 (Dako, diluted 1:10), 2008 within our investigation [10-14], summarized in CD23 (Nichirei, diluted 1:1), CD30 (Dako, diluted 1:40), Table 1, and its clinicopathological features have not CD45 (Dako, diluted 1:400), CD45RO (UCHL-1; Dako, been well described. Based on this Table 1, HS of the diluted 1:200), CD68 (KP-1; Dako, diluted 1:100), CD79a spleen can be potentially lethal condition that might re- (Dako, diluted 1:50), CD163 (Leica Microsystems, Wet- main asymptomatic or closely related with chronic zlar, Germany, diluted 1:200), lysozyme (Dako, diluted thrombocytopenia for a long time [11-13]. Even while 1:600), S-100 protein (Dako, diluted 1:900), fascin (Dako, diagnostic imaging findings have not been also charac- diluted 1:50), bcl-2 (Dako, diluted 1:30), myeloperoxi- terized satisfactorily, primary splenic HS cases often dase (MPO; Dako, dilutede 1:500), EMA (Dako, diluted show multi-nodular or nodular lesions in the enlarged 1:100), Cam5.2 (Becton Dickinson Immunocytometry tissues of spleen [10-14]. The patients of splenic HS have Systems, San Jose, CA, diluted 1:1), and HMB45 (Enzo a poor prognosis due to aggressive behavior with liver or Life Sciences Ltd., New York, diluted 1:100). Epstein- bone marrow infiltration, even though a splenectomy Barr virus (EBV) infection status was analyzed by in situ might induce temporary remission [11,14]. Therefore, hybridization for EBV-encoded RNAs using an Epstein- early accurate diagnosis and treatment before dissemi- Barr Early RNA Probe Reagent (EBER; Roche Applied nated proliferation of the HS tumor cells should improve Science, Lewes, UK). However, no chromosome studies their survival rates. have been performed. Indeed, this is not the first case reported. Despite that, we reported a very rare and unique surgical case Case presentation of primary splenic HS complicated with prolonged This patient had 4-year-history of idiopathic idiopathic thrombocytopenia, progressive pancytopenia, thrombocytopenia with non-response to steroid therapy hypo-albuminemia, hypo-γ-globulinemia, and secondary and progressive pancytopenia half year before a splenec- bone marrow involvement, which grossly presented as tomy (Figure 1A). There was no history of immunosup- splenomegaly with multiple peripheral infarction but pressive disorders, use of immunosuppressive medications, without any nodular foci. or unusual infections. The abdominal CT scanning showed heterogeneously enhanced and growing spleno- Materials and methods megaly without evidence of mass or nodular lesions, The patient was a 67-year-old Japanese female. The spe- measured approximately 130 × 80 mm in diameter cimen after fixation in 10% neutral buffered formalin (Figure 1B). Retrospectively, the clinical imaging examin- was embedded in paraffin for histological or ation also demonstrated mild splenomegaly, measured Table 1 Comparison of the main clinical features among the reported cases with primary splenic HS, including ours Case [reference] Age Sex CC Imaging or Gross features Weight of spleen Therapy Prognosis Involvement 1[10] 38 m Weakness multinodular 264 g S - - 2[11] 29 m edema nodular 735 g S(R+C) 5Y1M Liver 3[11] 60 m thrombocytopenia nodular 610 g S+C 1Y6M Liver, BM 4[11] 66 f edema, anemia multinodlar 750 g R+S+C 2Y6M Liver, BM 5[12] 71 f thrombocytopenia multinodlar 470 g C 6 M Hilum LN 6[13] 82 f Evans syn, multinodular 110 g R 1 M Liver 7[14] 58 f anemia nodular 800 g R+S+C 3 M - Present case 67 thrombocytopenia non-nodula 760 g S 6 M BM CC chief complaint, S surgery (splenectomy), R radiation, C chemotherapy, Y year, M month, BM bone marrow, LN lymph node. Yamada et al. Diagnostic Pathology 2012, 7:143 Page 3 of 7 http://www.diagnosticpathology.org/content/7/1/143 Figure 1 Summary of various clinical data before and after splenectomy, and the finding of an abdominal CT scan at surgery. (A) This patient showed prolonged idiopathic thrombocytopenia presenting with increased splenomegaly and non-response to steroid therapy. In addition, progressive pancytopenia, hypo-albuminemia, and hypo-γ-globulinemia coexisted. (B) The abdominal CT scanning revealed heterogeneously enhanced, severe splenomegaly without evidence of mass or nodular lesions. 48 × 39 mm or 95 × 34 mm in diameter 3 or 2 years proliferation of atypical