True histiocytic lymphoma: a morphologic, immunohistochemical, and molecular genetic study of 13 cases

Metastatic Histiocytic Sarcoma with Secondary Involvement of the Skin: A Case Report

Histiocytic sarcoma (HS) is a rare malignant neoplasm of presumed hematopoietic origin, showing morphologic and immunophenotypic evidence of histiocytic differentiation. A 61-year-old woman presented with an abdominal mass. She had a history of HS in both adrenal glands. The tumour cells of the left adrenal gland were very large epithelioid cells with abundant eosinophilic cytoplasm and large, round-to-oval nuclei. Similarly, the cutaneous lesion of the skin was composed of polygonal cells with well-defined cell borders and high nuclear/cytoplasm (N/C) ratios. Immunohistochemically, both tumours were positive for histiocyte-associated antigens but negative for epithelial, melanocyte, lymphoid, dendritic, and Langerhansl nuclei. Similarly, the cutaneous lesion of the skin was composenose correctly. It is important to recognise the morphological features and immunohistochemical characteristics of metastatic cells in order to achieve accurate diagnoses.

Multiple disciplinary team management of rare primary splenic malignancy: Two case reports

BACKGROUND

Malignant splenic tumors are rare but fatal, presenting a challenge in diagnosis and management involving hematology, oncology, and general surgery. By contrast, diagnosing and treating other common malignant tumors (such as lung and gastrointestinal cancer) offers multiple strategies for chemotherapy, radiotherapy, targeted therapy, and immunotherapy with the prospect of a cure. With various specialists involved in clinical multiple disciplinary team (MDT) discussion, personal bias can be minimized. It can also ignite important discussion which can benefit not only one patient but many patients.

CASE SUMMARY

Here, we report on the MDT diagnosis and management of the malignant splenic tumors littoral cell angiosarcoma and histiocytic sarcoma. Although only two cases of rare primary splenic malignancy are presented, MDT is a novel means of rare disease treatment.

CONCLUSION

To benefit patients, imaging analysis, safe operation, precise pathology examination, and individualized therapeutic treatment strategies are required. The involvement of various specialists in a clinical MDT discussion minimizes personal bias and can create important ideas to benefit all patients.

Diagnostic utility of flow cytometry in identifying histiocytic sarcoma-A case report

Histiocytic sarcoma (HS) is a malignant neoplasm of hematopoietic origin. It is an exceedingly rare and aggressive malignancy commonly seen in adults. Diagnosis is difficult owing to lack of specific clinical manifestations with the absence of precursor lesions or causative agents. Hence, it primarily relies on histopathological morphology combined with immunohistochemistry, which is time-consuming, hence resulting in delayed treatment. However, diagnostic utility of flow cytometry is not well established in this. We report a case of a 45-year-old man who presented with right axillary lymphadenopathy for 1 month. FNAC was performed on the axillary lymph node, which showed large, atypical lymphoid/histiocyte-like cells. On flow cytometry, these cells were CD64+, CD11c+, and CD45+ suggesting histiocytic sarcoma. Similar morphology was seen on incisional biopsy. On immunohistochemistry, the cells were negative for B and T cell markers, PAX5, EMA, CK, ALK, and CD1a and expressed CD68, S100, and CD11c. A diagnosis of histiocytic sarcoma was made. Hence, flow cytometry can be a highly effective and powerful tool for the early detection of HS and can help in prompt treatment, given its aggressive clinical course and low survival interval.

An advanced case of gastric histiocytic sarcoma treated with chemotherapy and gastrectomy: a case report and review of literature

Histiocytic sarcoma is a relatively new disease category and the gastrointestinal origin is sporadic. We report a case of a 74-year-old woman who underwent chemotherapy and proximal gastrectomy for extremely rare, advanced gastric histiocytic sarcoma. The resected specimen was subjected to numerous immunostainings to meet the diagnostic criteria of histiocytic sarcoma and was positive for the histiocyte markers' cluster of differentiation 68 and lysozyme. The markers of Langerhans cells, follicular dendritic cells, and myelocyte were all negative. Six reports of surgical resection of histiocytic sarcoma originating in the stomach exist, including our case. We reviewed the clinical course and the histological and immunohistochemical diagnostic features of surgically resected gastric histiocytic sarcoma.

Cutaneous Histiocytic Sarcoma With Cellular Cannibalism

Cutaneous histiocytic sarcoma (HS) is a rare malignant tumor. An 82-year-old woman presented with a 4 × 2-cm irregular-shaped red nodule on the left posterior scalp. A biopsy specimen revealed sheets of pleomorphic atypical cells in the dermis and subcutis. A diagnosis of HS was made based on the results of a panel of immunohistochemical stains that revealed positivity of leukocyte common antigen, CD4, CD163, and HLA-DR. At the time of resection, the tumor grew rapidly to 12 × 6.5 × 5 cm in size in 2 months. The resected tumor comprised round, oval, plasmacytoid, and spindled cells. Signet-ring cell type tumor cells were also observed. The histiocytic nature of HS was confirmed owing to the presence of cellular cannibalism, emperipolesis, Langhans giant cell-like cells, Touton giant cell-like cells, foreign-body giant cell-like cells, and hemosiderin laden cells. In some foci, a storiform pattern and fascicular pattern were occasionally observed. Local recurrence occurred shortly after resection. Subsequent radiation therapy showed insufficient effectiveness. It is challenging to make a diagnosis of HS without performing immunohistochemical studies; however, a variety of histiocytic features confirmed in hematoxylin and eosin-stained sections may suggest HS.

Thrombocytopenia with multiple splenic lesions - histiocytic sarcoma of the spleen without splenomegaly: A case report

BACKGROUND

Histiocytic sarcoma (HS) of the spleen is reported to be a rare and lethal disease. The clinicopathological features of splenic HS have not been well described. The objective of this paper is to describe the diagnosis and treatment of a case of this rare disease and provide a review of the literature.

CASE SUMMARY

In this article, we discuss the case of a 40-year-old Hispanic female who presented with progressive thrombocytopenia and multiple hypoechoic lesions in the spleen without splenomegaly. Positron emission tomography-computed tomography showed increased activity in cervical lymph nodes, as well as multiple bone and splenic lesions with positive uptake. Two bone marrow biopsies and fine-needle aspiration of the cervical lymph node were inconclusive. Laparoscopic splenectomy was performed, and gross examination showed a 110.1 g spleen with multiple rubbery, nodular lesions within the subcapsular sinus and splenic parenchyma. The microscopic findings showed multinodular histiocyte proliferation with atypia and multilobulated nuclei, which were positive for CD163, CD4, and CD68 by immunohistochemical analysis. The final pathologic diagnosis was difficult and was found to be low-grade HS of the spleen, after consultations with two renowned hematopathology institutions. At the patient’s five-month follow-up visit, her bone marrow metastasis had progressed. She is waiting to be enrolled in a clinical trial.

CONCLUSION

Pathologic diagnosis of splenic HS can be challenging. Low-grade differentiation may be associated with a slow progressive disease.

Primary cutaneous histiocytic sarcoma: A report of five cases with primary cutaneous involvement and review of the literature

INTRODUCTION

Histiocytic sarcoma is an extremely rare hematologic malignancy of histiocytic origin. Five cases of primary cutaneous histiocytic sarcoma are presented.

MATERIALS AND METHODS

Cases of primary cutaneous histiocytic sarcoma were identified using a natural language search from the dermatopathology data base of Cornell University.

RESULTS

There was a male predominance (4 males and 1 female) ranging in age from 33years to 92years (mean age of 73years); all presented with a solitary nodule which involved the head and neck area in four and thigh in one. The 73-year-old male had chronic myeloproliferative disorder. Biopsies showed a nonepitheliotropic dermal-based atypical large cell histiocytoid appearing infiltrate dermis showing positivity for common leukocyte antigen, CD4, CD14, CD68, CD163, CD2, CD11c, and lysozyme. Markers of terminal histiocytic differentiation such as S100, langerin, MXA, and CD83 were not seen. In two of the cases there was evidence of extracutaneous dissemination. The treatment in three of the cases was wide excision; there was no evidence of recurrent or metastatic disease. One case was given palliative radiation; the patient died. The other patient with underlying myelodysplastic syndrome died within a few weeks of initial cutaneous presentation.

CONCLUSION

HS must be differentiated from other malignant histiocytoid lesions. Staining for common leukocyte antigen and CD163 are the most reliable markers allowing this distinction. Patients who present with primary involvement of the skin may have a favorable outcome but only if treated relatively early in the course of the disease with complete excision.

Primary histiocytic sarcoma of the uterine cervix: an extremely rare entity

OBJECTIVE

Histiocytic sarcoma (HS) is an extraordinary rare tumor and it has an offensive clinical course. HS of the uterine cervix is a far uncommon tumor with just a few cases described so far. Here we presented a case of primary HS of the uterine cervix in a 62-year-old female initially misdiagnosed as large cell non-keratinizing squamous cell carcinoma. To the best of our knowledge, this is the first reported case of HS of the uterine cervix from Iran.

CASE REPORT

The patient presented with post-menopausal vaginal bleeding. Further evaluations revealed the presence of a relatively large cervical mass that was sampled. Under the preliminary diagnosis of large cell non-keratinizing squamous cell carcinoma, the patient underwent radical surgery. Postoperative pathological examination confirmed the diagnosis of HS of the uterine cervix. The patient received chemotherapy.

CONCLUSION

Clinical presentations of HS of the uterine cervix are very similar to more common cervical tumors; as a result its diagnosis relies on immunohistochemical methods. A correct diagnose could lead to the proper and timely treatment.

Non-mesenchymal Mimics of Sarcoma

A variety of different non-mesenchymal neoplasms may mimic sarcoma, in particular sarcomatoid carcinoma and melanoma, but also mesothelioma and rarely some lymphomas. This article reviews the key clinical and histologic features of such neoplasms in different settings, along with the use of ancillary studies to help identify the tumor types most frequently misdiagnosed as sarcoma.

Flow cytometry used to identify histiocytic sarcoma: A case report

Histiocytic sarcoma (HS) is an extremely rare but aggressive malignancy of hematopoietic origin. The diagnosis of HS mainly relies on pathological morphology and immunohistochemical staining combined with clinical symptoms. However, whether histiocytic sarcoma can be detected using flow cytometry (FCM) is not clear. We report the case of a 61-year-old female patient with a group of abnormal cells identified primarily by FCM. Largeabnormal cells -CD68⁺ CD11c⁺ CD14⁺ HLA-DR⁺ CD123⁺ CD45⁺ presented in upper forward scatter and side scatter, indicating that a malignancy originally derived from monocyte/macrophage could be histocytic sarcoma. This patient with histiocytic sarcoma was finally confirmed with pathology and immunohistochemistry. In conclusion, HS can be detected by assessment of CD68⁺ CD11c⁺ CD14⁺ HLA-DR⁺ CD123⁺ CD45⁺ cells using FCM, suggesting that FCM can be an effective tool for early finding of HS. © 2015 International Clinical Cytometry Society.

Genetic signature of histiocytic sarcoma revealed by a sleeping beauty transposon genetic screen in mice

Histiocytic sarcoma is a rare, aggressive neoplasm that responds poorly to therapy. Histiocytic sarcoma is thought to arise from macrophage precursor cells via genetic changes that are largely undefined. To improve our understanding of the etiology of histiocytic sarcoma we conducted a forward genetic screen in mice using the Sleeping Beauty transposon as a mutagen to identify genetic drivers of histiocytic sarcoma. Sleeping Beauty mutagenesis was targeted to myeloid lineage cells using the Lysozyme2 promoter. Mice with activated Sleeping Beauty mutagenesis had significantly shortened lifespan and the majority of these mice developed tumors resembling human histiocytic sarcoma. Analysis of transposon insertions identified 27 common insertion sites containing 28 candidate cancer genes. Several of these genes are known drivers of hematological neoplasms, like Raf1, Fli1, and Mitf, while others are well-known cancer genes, including Nf1, Myc, Jak2, and Pten. Importantly, several new potential drivers of histiocytic sarcoma were identified and could serve as targets for therapy for histiocytic sarcoma patients.

Histiocytic sarcoma : an updated literature review based on the 2008 WHO classification

Histiocytic sarcoma (HS) is an extremely rare malignant neoplasm showing morphologic and immunophenotypic evidence of histiocytic differentiation. The vast majority of previously reported HSs are now generally recognized to be misdiagnosed examples of non-Hodgkin lymphomas, predominantly diffuse large B-cell lymphoma or anaplastic large cell lymphoma. The recognition of such tumors parallels the development and widespread use of immunohistochemical techniques, along with the development of molecular genetic methods to detect immunoglobulin (IG) or T-cell receptor (TCR) gene rearrangement. The 2001 World Health Organization (WHO) definition of HS requires the absence of clonal B/T-cell receptor gene rearrangements. However, the 2008 WHO classification no longer strictly requires the absence of clonal immunoglobulin heavy chain (IGH) or TCR gene rearrangement for the diagnosis of HS. Recent studies demonstrated that HSs that occur subsequent to or concurrent with B- or T-lymphoblastic lymphoma/leukemia or mature B-cell neoplasms generally show clonal IgH and/or TCR gene rearrangement. These findings suggest the possibility of transdifferentiation of the two otherwise morphologically and immunohistochemically distinctive neoplasms. In addition, a recent study suggested clonal IG gene rearrangements may be detected at a high frequency in sporadic HS, indicating that a large subset of sporadic HSs may inherit the B-lymphocyte genotype. These findings provide new insights into the pathogenesis of HS, although the etiology of HS is still unknown. HS is a diagnosis of exclusion. It is necessary to rule out other diseases that could be misdiagnosed as HS with extensive immunophenotypical analysis before diagnosing HS.

Laparoscopic splenectomy for histiocytic sarcoma of the spleen

Primary histiocytic sarcoma of the spleen is a rare but potentially lethal condition. It can remain asymptomatic or only mildly symptomatic for a long time. An 81-year-old woman presented with an extremely enlarged spleen. She suffered from progressive anemia and required a red blood cell transfusion once a month. Although computed tomography, ultrasonography, and magnetic resonance imaging were performed for diagnosis, a confirmed diagnosis was not obtained. Her enlarged spleen compressed her stomach, and she suffered from gastritis and a sense of gastric fullness just after meals. She underwent laparoscopic splenectomy for therapeutic and diagnostic purposes. Her post-operative course was uneventful. After surgery, her red blood cell and platelet counts increased markedly. The tumor was diagnosed as splenic histiocytic sarcoma. Post-surgical chemotherapy was not performed, and the patient died of liver failure due to liver metastasis 5 mo after surgery. Laparoscopic splenectomy is minimally invasive and useful for the relief of symptoms related to hematological disorders. However, in cases of an enlarged spleen, optimal views and working space are limited. In such cases, splenic artery ligation can markedly reduce the size of the spleen, thus facilitating the procedure. The case reported herein suggests that laparoscopic splenectomy may be useful for the treatment of splenic malignancy.

Primary histiocytic sarcoma of the stomach: A case report with imaging findings

Histiocytic sarcoma (HS) is a rare malignant neoplasm that originates from a histiocytic hematopoietic lineage characterized by histiocytic differentiation and its corresponding immunophenotypic features. We herein reported a case of primary HS of the stomach which was confirmed through histopathologic examination and immunohistochemical staining. A 52-year-old woman presented with progressive difficulty in feeding and dull pain in the epigastric region. Gastroscopy, endoscopic ultrasonography, double contrast examination, and computed tomography revealed a mass located on the posterior wall of fundus and lesser curvature of the stomach. Microscopically, the cytoplasm of the tumor cells was abundant and eosinophilic. Immunohistochemical staining revealed that the tumor cells were positive for CD45RO and CD68. It is difficult to differentiate HS of stomach from other gastric malignancies by radiological evaluation alone. However, HS may be considered when a protruding and ulcerated mass in stomach shows heterogeneous hypervascular features. To the best of our knowledge, this is the first report in English language literature that emphasizes the imaging findings of human gastric HS.

[Unusual lung localization of histiocytic sarcoma]

Histiocytic sarcoma, proliferation araising from immunoregulatory effector system cells, is a very rare and recently recognised tumor. Diagnosis is based on immunohistochemistry and molecular genetic techniques, which allow to distinguish histiocytic sarcoma from lymphocytic proliferation, such as non-Hodgkin's. We report this rare case of multivisceral histiocytic sarcoma revealed by lung localization and for which the evolution was fatal.

Tumor-associated primo vascular system is derived from xenograft, not host

The primo vascular system (PVS), which is composed of very small primo-vessels (PV) and primo-nodes (PN), has recently emerged as a third component of circulatory system. Here, we report the presence of a tumor derived PVS in murine xenografts of human histiocytic lymphoma (U937) in close proximity to the tumor. Within this system, PNs are small (~500-600 μM diameter) membranous sac-like structures which contain numerous small cells which can be demonstrated by DAPI staining. Hematoxylin and Eosin (H&E) staining of the peri-tumoral PVS shows the presence of loose structures lined by fibroblasts but filled with dense fibers, cells, lacunae and nerve-like structures. The origin and type of cells within the PVS was characterized by immunostaining with antibodies for CD68, CD45 and lysozyme. The results of these studies reveal that the PVS of the xenograft originates from the human U937 tumor cells. qRT-PCR analysis of mRNA isolated from PVS cells reveals a striking predominance of human, rather than mouse, sequences. Of particular interest, human stem cell specific transcription factors were overexpressed, most notably KLF4, an upstream regulator of NANOG which maintains the pluripotent and undifferentiated state of stem cells. These results suggest that the cells present within the PVS are derived from the human xenograft and suggests that the primo-vessels associated with the xenografted tumor may provide a safe haven for a select population of cancer stem cells. Further understanding of the biological properties of these cells may allow the development of new anti-cancer interventions.

Total en bloc spondylectomy of L3 vertebra for histiocytic sarcoma

This article describes a rare malignant spinal tumor successfully treated with total en bloc spondylectomy via a posterior approach. The purpose of this study was to emphasize the occurrence of primary histiocytic sarcoma in the lumbar spine. Histiocytic sarcomas are rare, malignant neoplasms of the lymphohematopoietic system that usually occur in the skin, lymph nodes, and intestinal tracts. Primary spinal column histiocytic sarcoma is rare. To the authors' knowledge, no reports have been published of treating this tumor with total en bloc spondylectomy.A 27-year-old woman presented with a 2-month history of intermittent low back pain and right lower extremity pain. Magnetic resonance imaging and computed tomography (CT) revealed a lumbar vertebra tumor. Positron emission tomography/CT showed focal accumulation in the tumor site. The patient was diagnosed with a histiocytic sarcoma based on biopsy findings and underwent total en bloc spondylectomy of L3 and reconstruction via a posterior approach. The patient maintained normal neurologic function, and the pain was lessened. No major complications occurred. No radiotherapy or chemotherapy was administered postoperatively, and no local tumor recurrence or distant metastases existed at 2-year follow-up.The diagnosis of histiocytic sarcoma relies predominantly on the verification of histiocytic lineage and the exclusion of other, poorly differentiated, large-cell malignancies by immunohistochemical stain. Total en bloc spondylectomy at L3 via a posterior approach can be performed safely and is an important approach in the treatment of selected spinal tumors.

Primary extranodal histiocytic sarcoma of lumbar spine

A 17-year-old male patient presented with lower back pain and weakness of lower limbs. On radiological investigation, a destructive bony lesion involving the third lumbar vertebra was seen associated with soft tissue extension and an extradural component. The lesion was surgically excised in view of the rapidly progressing symptoms. The histologic diagnosis was histiocytic sarcoma. Further investigations did not reveal any other lesion elsewhere. The case is being presented in view of the uncommon occurrence of a primary extranodal histiocytic sarcoma of the lumbar spine, which simulated a primary bone tumor.

Complete response of a patient with advanced primary splenic histiocytic sarcoma by treatment with chemotherapeutic drugs selected using the collagen gel droplet-embedded culture drug sensitivity test

A 69-year-old man presented with multiple nodules on the spleen and liver that had been detected by computed tomography (CT). A liver tumor biopsy was performed, and the patient was diagnosed to have histiocytic sarcoma (HS). Splenectomy was performed, and the chemosensitivity of the spleen tumor was measured using the collagen gel droplet-embedded culture drug sensitivity test (CD-DST). Hepatic arterial infusion chemotherapy was administered, based on the results of the CD-DST. The patient achieved complete remission (CR) after this therapy and remained alive without recurrence at the final follow-up. This is the first known case of CR in response to chemotherapy for advanced splenic HS.

Histiocytic sarcoma of the parotid gland region

Histiocytic sarcoma (HS) is a malignant neoplasm showing the morphological and immunophenotypic features of mature histiocytes. Reported herein is a case of HS of the parotid gland region. A 53-year-old woman noticed a swelling of the right preauricular area. Preoperative fine needle aspiration cytology showed an admixture of pleomorphic atypical cells and mature lymphocytes. She underwent total parotidectomy. Grossly, the tumor was located at the parotid gland to subcutaneous tissue, and showed infiltrative growth with massive necrosis and hemorrhage. Microscopically, the tumor was composed of marked pleomorphic cells with eosinophilic cytoplasm. Bizarre multinuclear giant cells were scattered and intermingled. Tumor cells were positive for CD68 (KP-1 and PG-M1), CD163, S-100 protein, CD1a, CD4 and CD31, but negative for CD3, CD20, CD21, CD79a, DEC205 and langerin, immunohistochemically. Monoclonal proliferation of B cells was not confirmed on polymerase chain reaction for IgH. The patient had recurrent lesions in the pelvis and stomach 5 months after parotidectomy and died of the disease 10 months after the operation.

Synchronous histiocytic sarcoma and diffuse large B cell lymphoma involving the stomach: a case report and review of the literature

We present a 62-year-old Chinese woman with histiocytic sarcoma (HS) and diffuse large B cell lymphoma (DLBL) located in the stomach. HS showed abundant eosinophilic cytoplasm with large, pleomorphic nuclei. Tumor giant and multinucleated cells were also prominent. Hemophagocytosis was common in the neoplastic cells. These cells were positive for CD68, CD45RO, and leukocyte common antigen (LCA), partly positive for S-100 and lysozyme, and negative for CD3, CD5, CD20, Pax-5, CD79a, CD1a, CD21, CD35, CD34, myeloperoxidase, HMB45 and cytokeratin (CK). These cells invaded the submucosa, muscularis mucosa, and serosa. DLBL was located in the mucosa and engulfed the covering epithelium and gland. The nuclei of tumor cells were medium-to-large in size, being ≥twice the size of normal lymphocytes. They were diffusely positive for CD20, Pax-5, and LCA, partly positive for vimentin, CD79a, CD10, CD30, CD15, and epithelial membrane antigen, and negative for S-100, CD1a, CD21, CD5, cyclin D1, CD23, CD35, HMB45, and CD68. Both types of tumor cell were positive for Oct-2, Bcl-2, and Bcl-6. These results suggest that HS may have shared a common clonal origin with DLBL, or may have transdifferentiated from DLBL The patient refused further chemotherapy, and died 7 months after surgical resection.

The histopathologic and molecular basis for the diagnosis of histiocytic sarcoma and histiocyte-associated lymphoma of mice

Histiocytic sarcoma (HS) and histiocyte-associated lymphoma (HAL) of mice are difficult to distinguish histologically. Studies of multiple cases initially diagnosed as HS or HAL allowed us to define HS as round, fusiform, or mixed cell types that were F4/80+, Mac-2+, and PAX5-; that lacked markers for other sarcomas; and that had immune receptor genes in germline configuration. Two other subsets had clonal populations of lymphocytes. The first, HAL, featured malignant lymphocytes admixed with large populations of normal-appearing histiocytes. The second appeared to be composites of lymphoma and HS. Several cases suggestive of B myeloid-lineage plasticity were also observed.

Histiocytic sarcoma with interdigitating dendritic cell differentiation: a case report with fine needle aspiration cytology and review of literature

A hybrid histiocytic sarcoma-interdigitating dendritic cell sarcoma was found in a small perinephric lymph node of an asymptomatic 80-year-old man, who presented a year ago with two small foci of lung metastasis found during routine chest X-ray. Fine needle aspiration cytology demonstrated interconnecting long and thin cell processes radiating from dendrite-like neoplastic cells with oval, enlongated, reniform, and irregular nuclei with vesicular chromatin and distinct nucleoli. Histology showed spindled epitheliod and histiocytic cells with abundant, slightly eosinophilic cytoplasm with indistinct cell borders and forming fascicles in a vague storiform pattern with interspersed T-lymphocytes. Immunohistochemically, the neoplastic cells were strongly positive for histiocytic markers: CD163, CD68, lysozyme, and PU.1, as well as strongly positive for dendritic cell markers: S100 and fascin, but were negative for CD1a (Langerhans cell marker), CD21/CD35 (follicular dendritic cell markers), B-cell, and T cell markers. This case is compared to the four hybrid histiocytic-dendritic sarcomas reported since 1983.

A case of primary histiocytic sarcoma arising from thyroid gland

Histiocytic sarcoma (HS) is an extremely rare true histiocytic malignancy. We report a case of HS arising from thyroid gland in a 69 year-old man. Following subtotal thyroidectomy, a histopathologic, immunohistologic, and genotypic examination revealed HS. This tumor was composed of large spindle or round epithelioid cells with abundant eosinophilic cytoplasm. The neoplastic cells were positive for macrophage-associated antigen CD68, CD163, and lysozymes, as well as CD45, HLA- DR, DP, DQ, and S100, most consistent with a diagnosis of HS. The BIOMED-2 multiplex PCR analysis showed polyclonal B- and T-cell populations. To our knowledge, this is the first report of a rare entity HS involving thyroid gland using a comprehensive immunophenotyping panel including CD163 as well as molecular studies to establish the true histiocytic nature of these lesions.

Pulmonary histiocytic sarcoma mimicking pulmonary Langerhans cell histiocytosis in a young adult presenting with spontaneous pneumothorax: a potential diagnostic pitfall

We present a case of a histiocytic sarcoma incidentally detected in peripheral lung tissue resected for a spontaneous pneumothorax. Furthermore, we discuss the practical approach to pulmonary Langerhans cell histiocytosis, the main differential diagnosis of this lesion in the lung, based on morphological and immunohistochemical features. A 23-year-old male patient presented with recurrent pneumothoraces. The pulmonary tissue showed a single round granuloma-like lesion measuring 4 mm in diameter in close neighbourhood to a bronchial wall. The granuloma consisted of histiocytic cells with enlarged pale nuclei, plasma cells, lymphocytes and scanty eosinophilic granulocytes giving the impression of a granuloma of pulmonary Langerhans cell histiocytosis on haematoxylin and eosin (H&E) stains. Immunohistochemically, the histiocytic cells were negative for CD1a and S-100. They were positive for CD68, HLA-DR, CD14, CD4, CD11c, CD45LCA and lysozyme. MIB1 (Ki67) showed a nuclear staining of approximately 10% of the histiocytic cells. In summary, these findings were in keeping with a histiocytic sarcoma, a rare haematopoetic neoplasm. By demonstrating this particular case, we emphasise the importance of proving the diagnosis of pulmonary Langerhans cell histiocytosis by means of immunohistochemistry. In case of a negative CD1a reaction in a histiocytic lesion, further immunohistochemical studies have to be performed in order not to misdiagnose a malignant haematopoetic lesion.

Primary histiocytic sarcoma of the spleen associated with hemophagocytosis

We report a patient with primary histiocytic sarcoma of the spleen associated with prominent hemophagocytosis. Although thrombocytopenia, probably due to hemophagocytosis, was refractory to corticosteroid therapy, the transfusion of platelets, and splenic irradiation, partial splenic embolization was effective and facilitated splenectomy for a diagnosis. The majority of the spleen showed necrosis, but viable neoplastic cells with pleomorphic nuclei and abundant cytoplasm, showing occasional erythrocytes or leukocytes, were still discernible. The neoplastic cells expressed CD68, lysozyme, and S-100 protein, and were negative for lymphoid, myeloid, and epithelial cell markers. CD163, a monocyte/macrophage-specific molecule, was positive in only some of them. Despite multiagent chemotherapy, the patient died of the disease, showing a rapidly progressive clinical course. Although the preoperative diagnosis of primary splenic histiocytic sarcoma is difficult, it has been confirmed in patients with splenomegaly of unknown etiology that clinicolaboratory features suggestive of hemophagocytosis may be important clues suggestive to the disease. CD163 expression by neoplastic cells could be confirmed only after careful observation, because the molecule may only be seen in some of the neoplastic cells.

Histiocytic sarcoma – A case with evenly distributed multinucleated giant cells

Histiocytic sarcoma is an uncommon neoplasm of mature histiocytes with a poor clinical outcome. We report a case of a true histiocytic sarcoma with prominent and evenly distributed multinucleated giant cells that mimics a giant cell tumor of soft tissue. The tumor was located between the appendix, right ovary, and the terminal ileum with severe adhesion. The liver and spleen were not enlarged. Grossly, the tumor appeared grayish white, solid, and soft. Microscopically, polygonal mononuclear tumor cells aggregated to form somewhat epithelioid nests, which occasionally showed coagulative necrosis. Prominent and evenly scattered giant cells were present in all sections. In addition, tumor cell infiltration was noted in regional lymph nodes. The tumor cells were positive for lysozyme, CD68, CD163, and negative for T- and B-cell lineage markers, follicular dendritic cell, megakaryocytic, epithelial, muscular, and melanocytic markers, CD1a and CD30. This case posed great difficulty in clinical and pathological diagnoses. Gross pictures, microscopic findings, and extensive immunostains are important for the differential diagnosis.

Gastrointestinal stromal tumors: differential diagnosis

Availability of KIT tyrosine kinase inhibitors for specific treatment of GISTs has magnified the importance of accurate differential diagnosis of GIST from other tumors occurring in the GI tract and abdomen. The general problems in this distinction include histological mimicry of other mesenchymal tumors with GIST, occasional KIT-negativity of GIST, and KIT-positivity of non-GISTs. Up to 5% to 10% gastric GISTs and <2% of intestinal GISTs can be KIT-negative. The identification of these tumors as GISTs is based on knowledge of the spectrum of GIST morphology, and can be supported by molecular diagnosis of KIT and PDGFRA mutations (the latter pertain to gastric tumors). True smooth muscle tumors (rare in GI tract except in esophagus and colon) can be separated from GISTs by the eosinophilic tinctorial quality of tumor cells, positivity for smooth muscle markers, and negativity for KIT. Desmoids can form large GIST-like masses, but are composed of spindled or stellate-shaped cells in a densely collagenous stroma. Negativity for KIT and nuclear positivity for beta-catenin are differentiating features. GI schwannomas, melanoma, and rare primary clear cell sarcoma are S100-positive, usually with characteristic histology. The latter two can be KIT-positive. KIT-positive non-GISTs include some sarcomas, especially angiosarcoma and Ewing sarcoma, extramedullary myeloid tumor, seminoma, and a few carcinomas, notably small cell carcinoma of lung. Spurious KIT-positivity, seen with some polyclonal KIT antibodies, has been a source of confusion leading to probable false-positive results in fibroblastic tumors and occasional other sarcomas, such as leiomyosarcomas. Integration of histological features with carefully standardized immunohistochemistry, supported by KIT and PDGFRA mutation analysis, is the cornerstone of state-of-the art differential diagnosis of GIST. To comprehensively capture all GISTs, KIT immunostains should be performed on all unclassified epithelioid and mesenchymal tumors of the abdomen. This is a US government work. There are no restrictions on its use.

Primary histiocytic sarcoma arising in the head and neck with predominant spindle cell component

This is the first case report of Histiocytic Sarcoma (HS) with predominant spindle cell component occurring in the head and neck region of a 41-year-old man. The tumor was composed of sheets of large round to oval cells with pleomorphic vesicular nuclei, prominent nucleoli and abundant eosinophilic cytoplasm. Multinucleated forms, numerous mitoses, and tumor necrosis were also noted. Sheets, fascicles, and whorls of spindle cells with spindled to ovoid vesicular nuclei, small to medium-sized distinct nucleoli, and eosinophilic cytoplasm were frequently observed. Immunohistochemical staining in the tumor cells was positive for CD163, CD68, lysozyme, CD45, and NSE. Focal expression of CD4 and S-100 was also noted. Electron microscopy demonstrated an abundance of lysosomes in the cytoplasm of tumor cells. Chromosome study revealed a 57–80 hyperdiploid [7]/46, XY [13] karyotype, including 3 to 4 copies of various chromosomes. The immunohistochemical and ultrastructural findings confirmed the diagnosis of HS.

Malignant histiocytosis: a case report of a rare tumour presenting with spontaneous splenic rupture

Malignant histiocytosis is a rare invasive proliferation of neoplastic histiocytes. Cases previously reported as malignant histiocytosis were shown to be lymphomas of T or B lineage, especially anaplastic large-cell lymphomas. A case of malignant histiocytosis is described, in which a patient presenting with symptoms suggestive of pneumonia suddenly deteriorated and died. At autopsy, a large quantity of fresh blood, originating from several ruptured nodules on the enlarged spleen, was seen in the peritoneal cavity. Extensive infiltration by pleomorphic tumour cells and erythrophagocytosis by tumour cells were seen on histological examination of the spleen. Immunohistochemical analysis and staining were carried out. This is the second reported case of malignant histiocytosis presenting with spontaneous splenic rupture.

Reticulohistiocytoma (Solitary Epithelioid Histiocytoma)

Reticulohistiocytoma and multicentric reticulohistiocytosis are designations for uncommon, incompletely characterized histiocytic proliferations of the skin or soft tissues. In this study, we analyzed a uniform group of 44 lesions composed of epithelioid histiocytes, comprising a subset of lesions originally designated as reticulohistiocytoma, and propose designating them as "solitary epithelioid histiocytoma" (SEH), in line with the recently published classification proposal for histiocytic disorders. There were 26 males and 18 females with a median age of 35 years (range, 2.5-74 years). All patients had a superficial, circumscribed, mildly elevated, solitary lesion (size range, 1.5-11 mm; median, 4 mm), located in the trunk wall (n = 16), lower extremity (n = 12), head and neck (n = 8, including 2 in the oral cavity), upper extremity (n = 6), penis (n = 1), and an unspecified site (n = 1). Histologically, the lesions typically involved upper and mid-dermis and were not ulcerated. They were composed of large epithelioid histiocytes with a varying number of lymphocytes and neutrophils. The histiocytes had abundant, typically densely eosinophilic, cytoplasm and mostly mild, if any, nuclear atypia. Multinucleated forms with randomly oriented nuclei were also present. The histiocytes had low mitotic activity (range, 0-4 mitoses per 10 wide HPFs; median, 1 mitosis per 10 HPFs). The lesions contained varying numbers of CD3-positive T cells, whereas B lymphocytes, plasma cells, eosinophils, and mast cells were scant, if present at all. Immunohistochemically, the epithelioid histiocytes were positive for CD163, CD68, lysozyme (variably), and vimentin. They often had focal nuclear immunoreactivity for microphthalmia transcription factor, and they sometimes had focal reactivity for Factor XIIIa and S-100 protein. Membrane positivity for CD31, CD43, and CD45 was variable. The epithelioid histiocytes were consistently negative for CD3, CD20, CD30, HMB45, and keratins. All 12 patients with follow-up information had an uneventful clinical course with no recurrences (median, 13 years). SEH is a benign, probably reactive, histiocytic proliferation of unknown etiology. It needs to be distinguished from Rosai-Dorfman disease, juvenile xanthogranuloma, a variety of granulomatous conditions, and some malignant neoplasms, including histiocytic sarcoma, melanoma, and epithelioid sarcoma.

Atypical Presentation of Rosai-Dorfman Disease in the Lacrimal Gland Mimicking Malignancy

A 29-year-old man presented with a painful, rapidly growing mass in the right upper eyelid. Ophthalmic and systemic examinations and results of laboratory investigations were all normal. CT revealed a mass in the right lacrimal region with surrounding bone destruction, which was suggestive of a malignant lacrimal gland tumor. Histologic analysis of the biopsy specimen supported a diagnosis of Rosai-Dorfman disease with no lymphadenopathy.

Mediastinal germ cell tumor associated with histiocytic sarcoma of spleen: case report of an unusual association

We present an unusual association of mediastinal germ cell tumor containing seminoma and angiosarcoma components and splenic histiocytic sarcoma. A 15-year-old boy presented with chest pain. Histopathologically, an anterior mediastinal mass contained typical seminoma, immature teratoma, embryonal carcinoma, angiosarcoma, yolk sac tumor, and polyembryoma. An abdominal ultrasonogram revealed a huge splenomegaly with multiple ill-defined low echogenic nodules, 1 month after the second cycle of chemotherapy. Histopathologically, large, round-to-oval tumor cells with abundant eosinophilic cytoplasm often contained eccentrically placed nuclei with vesicular chromatin and an irregular nuclear membrane. The tumor cells were immunoreactive for CD68, CD31, and CD4. The cytogenetic results showed deletion of the long arm of chromosome 5 and trisomy 8. This lesion might have been on the pathway of multistep tumorigenesis toward a final leukemia.

Histiocytic sarcoma in a 3-year-old male: a case report

We describe a pediatric patient with histiocytic sarcoma involving the T6 and L4 vertebral bodies and the lungs. His tumor progressed during chemotherapy designed for Langerhans' cell histiocytosis and sarcoma. High-dose radiation, on the other hand, was effective.

Histiocytic sarcoma: a study of five cases including the histiocyte marker CD163

Histiocytic sarcoma (HS) is a rare but controversial hematopoietic neoplasm. In the past, malignancies have been misclassified as histiocytic tumors due to overlapping histologic features and inadequate phenotypic data. CD163, a recently characterized hemoglobin scavenger receptor, appears to be a 'specific' marker of histiocytic lineage and a promising diagnostic tool for evaluating histiocytic neoplasms. Five cases of HS were studied to further elucidate the clinicopathologic features of these rare tumors and to demonstrate the diagnostic utility of CD163. Criteria for diagnosis included histologic and immunohistochemical evidence of histiocytic differentiation, CD45 positivity, and exclusion of lymphoid, epithelial, melanocytic and dendritic cell phenotype. Sites of disease included the colon (two cases), palate, inguinal lymph node, and testis. The clinical course was aggressive in 4/5 patients (survival=2-15 months). One patient with localized disease of the palate, survived 17 years after diagnosis. All patients with poor survival had tumors > or =3.5 cm. Histologically, all cases showed diffuse architecture with large, discohesive polygonal cells. Spindling of cells was focally noted. Hemophagocytosis was identified in 3/5 cases. A prominent inflammatory background was present in 4/5 tumors. All cases were immunoreactive for CD45, CD163, CD68, and lysozyme. S-100 was focally positive in 4/5 cases. Antibodies for melanocytic, epithelial, lymphoid, and dendritic cell markers were negative. Molecular studies showed monoclonal IgH gene rearrangements in three cases. Our findings suggest that HS is an uncommon neoplasm frequently extranodal in presentation and aggressive in behavior, with rare exceptions. Stage of disease and possibly tumor size are significant prognostic indicators. Molecular studies remain controversial in the diagnosis. The morphologic and phenotypic features are relatively uniform; however, the diagnosis requires exclusion of more common neoplasms by extensive immunophenotypic studies. CD163 appears to be a specific histiocytic marker and is important in establishing the diagnosis of HS.

Monocyte/Macrophage-specific marker CD163+ histiocytic sarcoma: case report with clinical, morphologic, immunohistochemical, and molecular genetic studies

We report a case of a very rare disorder, histiocytic sarcoma, from a review of our autopsy cases. The neoplastic cells that proliferated in organs throughout the body were large cells containing eosinophilic cytoplasm and pleomorphic nuclei with prominent nucleoli. In the bone marrow, erythrophagocytosis by neoplastic cells was observed. The neoplastic cells were positive not only for lysozymes and CD68 (KP-1, PG-M1, and Ki-M1P) but also for a monocyte/macrophage-specific marker, CD163. In contrast, the results of tests for markers of myeloid cells, lymphoid cells, and epithelial cells were all negative. In a polymerase chain reaction study of paraffin-embedded tissues, analyses for the rearrangement of immunoglobulin heavy chain and T-cell receptor-gamma genes were negative. The current World Health Organization diagnostic criteria for histiocytic sarcoma regard immunohistochemical investigation as crucial. In this regard, the highly specific positivity for CD163 in this patient indicates that immunohistochemical staining of CD163 is very useful for the diagnosis of histiocytic sarcoma.

Histiocytic sarcoma with fatal duodenal ulcers

Histiocytic sarcoma is an uncommon neoplasm of mature histiocytes with very poor outcome. We report an autopsy case of a true histiocytic sarcoma with characteristic symptoms of so-called "malignant histiocytosis of the intestine". The liver and spleen were enlarged, with remarkable tumor cell infiltration in the hepatic sinusoids and splenic sinuses. Tumor cells aggregated to form sporadic nodular lesions in the liver, which often showed coagulative necrosis. Infarcted lesions also occurred at the splenic subcapsular area. In addition, tumor cell infiltration was noted in the sinuses of bone marrow and lymph node. Tumor cells often demonstrated moderate pleomorphism with multinucleated giant cells. They were positive for CD68 and negative for T- and B-cell lineage markers, megakaryocytic markers, and CD30. Various examinations were done to rule out infection-associated hemophagocytic syndrome, and the absence of infectious diseases was revealed. Thus, the diagnosis of histiocytic sarcoma was made. Apart from these lesions, multiple ulcerations, some with fatal perforation, were found in the esophagus and duodenum. They showed only non-specific inflammatory changes without tumor cell involvement. The ulcers probably derived from ischemic condition through an embolic process caused by tumor cell infiltration elsewhere in the blood vessels at the periphery of the ulcers.

Extranodal histiocytic sarcoma: clinicopathologic analysis of 14 cases of a rare epithelioid malignancy

Histiocytic sarcoma is a rare malignant neoplasm that occurs in lymph nodes, skin, and the gastrointestinal tract. Many previously published cases were likely misdiagnosed examples of non-Hodgkin lymphoma. Only small numbers of bona fide examples exist in the world literature; cases arising primarily at extranodal sites are not well described and often seem to go unrecognized. To characterize these tumors further, 14 extranodal histiocytic sarcomas were analyzed. Hematoxylin and eosin sections were reexamined, immunohistochemistry was performed, and clinical details were obtained from referring hospitals. Eight patients were female and 6 male (median age, 55 years; range, 15-89 years). All patients presented with a solitary mass, ranging in size from 1.8 to 12 cm (median 6.8 cm). Seven tumors arose in soft tissue (6 lower limb; 1 upper limb), 5 in the gastrointestinal tract (1 involving both stomach and colon, 1 ileum, 2 rectum, 1 anus), 1 in the nasal cavity, and 1 in the lung. Three gastrointestinal tract tumors also involved regional lymph nodes, and 1 involved the liver. Most cases had infiltrative margins. The tumors were generally composed of sheets of large epithelioid cells with abundant eosinophilic cytoplasm, oval to irregular nuclei, vesicular chromatin, and large nucleoli. Binucleated cells were common, and 6 cases contained tumor giant cells. Mitoses ranged from 1 to 64 per 10 HPF (median 11 per 10 HPF). Necrosis was present in 8 cases. Nearly all tumors showed a striking inflammatory infiltrate, most often of neutrophils or lymphocytes. All cases were reactive for LCA, CD45RO, and CD68 (KP1 and PG-M1); 13 of 14 (93%) expressed CD4, 12 of 14 (86%) lysozyme, 8 of 10 (80%) CD31, 7 of 14 (50%) S-100 protein, and 5 of 14 (36%) focal CD1a. Two tumors showed weak, focal cytoplasmic positivity for CD30, and 1 for epithelial membrane antigen. The tumors were negative for ALK-1, CD21, CD35, CD3, CD20, CD34, myeloperoxidase, HMB-45, and keratins. Gastrointestinal tract cases were negative for c-kit and desmin. Six patients were treated with postoperative radiation and 7 with chemotherapy (CHOP or ProMACE-MOPP). Follow-up was available for 10 patients (median, 24 months; range, 4 months to 11 years). Two tumors recurred locally, and 5 patients developed distant spread: 3 to lymph nodes, 1 to lung, and 1 to bone. At the last follow-up, 2 patients have died of disseminated disease, 4 and 5 months following initial diagnosis. The patients who died thus far had the largest primary tumors. Histiocytic sarcoma may arise primarily in soft tissue and shows reproducible histologic features, including abundant eosinophilic cytoplasm and a prominent inflammatory infiltrate. Metastatic carcinoma, metastatic melanoma, and large cell non-Hodgkin lymphomas should be excluded by immunohistochemistry. Histiocytic sarcoma has the potential for an aggressive clinical course, most often with lymph node involvement. However, a subset of cases presenting with clinically localized disease have a favorable long-term outcome. Tumor size may be a prognostic factor.

Histiocytic Sarcoma Associated With Idiopathic Myelofibrosis

We describe the case of a 39-year-old man with idiopathic myelofibrosis, who developed histiocytic sarcoma (true histiocytic lymphoma) 6 months after diagnosis. The patient developed generalized lymphadenopathy. A lymph node biopsy showed pronounced distension of the sinuses in the medulla and periphery, caused by the accumulation of large tumor cells. The tumor cells had abundant clear or eosinophilic cytoplasm. The nuclei were of various sizes and shapes, with condensed chromatin and prominent nucleoli. Some tumor cells displayed erythrophagocytosis. Immunohistochemically, the tumor cells were positive for CD68, α1-antitrypsin, CD45, CD45RO, and S100 protein, and were negative for B- and T-cell markers, CD30, CD1a, lysozyme, myeloperoxidase, factor VIII–related antigen, CAM 5.2, and HMB-45. Despite multiagent chemotherapy, the patient died of disease 25 months after diagnosis. Although histiocytic sarcomas are very rare, their recognition may be important for clinical and prognostic reasons.

Primary histiocytic sarcoma of the spleen associated with erythrophagocytic histiocytosis

We report an exceptional case of a histiocytic sarcoma presenting as a primary isolated spleen tumor in a 71-year-old woman. The neoplastic cells in the cords and sinuses of the red pulp formed multiple lobulated tumors, which were detected in vivo by ultrasound scan. The medium cells, large cells and the giant cells expressed CD68, a histiocyte-associated marker, lysozyme and S100 protein. All these cells were negative for B- and T-cell markers, cytokeratins, melanosome markers (HMB45) and CD1a (Langerhans' cells). Many tumor cells displayed strong erythrophagocytosis and sometimes lymphocytophagocytosis. In addition, numerous histiocytes with morphology indistinguishable from reactive macrophages also exhibited a strong erythrophagocytosis, and were found in the tumor as well as in the normal splenic parenchyma. Despite multi-agent chemotherapy, the patient suffered from a relapse in the liver, with a rapid fatal outcome. A literature review showed that such a primary splenic presentation with multiple tumors is rare. In contrast, in systemic malignant histiocytosis, secondary spleen involvement occurs more frequently but with diffuse infiltration. The association with a reactive histiocytosis with erythrophagocytosis corresponds to "histiocytic medullary reticulosis", as previously described by Scott and Robb-Smith.