Mediastinal mixed dendritic cell sarcoma with hybrid features

This report describes a recurrent sarcoma involving the soft tissues of the posterior mediastinum with features of both follicular dendritic and interdigitating dendritic cells. Histologically, the tumour, which was a recurrent neoplasm 19 years after the initial removal, was composed of bland spindle shaped cells with interspersed inflammatory cells, predominantly lymphocytes. Immunohistochemically, the spindle cells were positive for S100 protein, CD45, CD68, and vimentin, but negative for CD21 and CD35 (markers of follicular dendritic cells). The immunophenotype was in keeping with interdigitating dendritic cells. However, ultrastructural examination demonstrated elongated cell processes joined by desmosome-like junctions-features in keeping with follicular dendritic cells. Follicular dendritic cell sarcoma and interdigitating dendritic cell sarcoma are rare neoplasms and a high index of suspicion is required to make a correct diagnosis. Immunohistochemistry and/or electron microscopy are required for a definitive diagnosis. This case shows that hybrid neoplasms can occur, which have features of both follicular and interdigitating dendritic cells.     

Interdigitating dendritic cell sarcoma of the duodenum with rapidly fatal course: a case report and review of the literature

Interdigitating dendritic cell sarcoma is an extremely rare malignancy derived from antigen-presenting cells. Dendritic cells constitute a heterogeneous group of cells, which includes Langerhans cells, dermal dendrocytes, follicular dendritic cells, and interdigitating dendritic cells present in lymphoid and nonlymphoid organs. We report the case of a 36-year-old woman who presented with epigastric pain, projectile vomiting, and significant weight loss. Upper gastrointestinal endoscopy showed a duodenal lesion; a biopsy of the lesion was taken and was diagnosed as sarcoma. She underwent a Whipple procedure. A final diagnosis of interdigitating dendritic cell sarcoma was made, with liver and peripancreatic lymph node involvement. The patient deteriorated rapidly and died 4 months later. Although interdigitating dendritic cell sarcoma of the duodenum is extremely rare, we think it should be included in the differential diagnosis of unusual spindle cell tumors with a rich lymphocytic infiltrate.     

Dysplastic follicular dendritic cells in hyaline‐vascular Castleman disease: a rare occurrence creating diagnostic difficulty

Follicular dendritic cell (FDC) proliferations and dysplastic FDCs can be seen in Hyaline‐vascular Castleman disease (HVCD). The association between HVCD and FDC sarcoma is well‐documented; dysplastic FDCs may be precursors to FDC sarcoma. Herein, we describe a case of HVCD with strikingly large and dysplastic FDCs, which raised the differential of Hodgkin lymphoma and other neoplasms. Scattered dysplastic FDCs were predominantly in germinal centers and mantle zones, and rarely in interfollicular areas. Although occasional germinal centers contained increased FDCs, no mass forming proliferations were present to suggest FDC sarcoma. Immunostaining demonstrated that the atypical FDCs expressed CD21, clusterin and CXCL13, but not CD23, S100, pankeratin or CD30; they aberrantly expressed epidermal growth factor receptor (EGFR). The present case demonstrates that dysplastic FDCs may be present as isolated cells that require immunophenotyping to distinguish them from malignant entities with similar morphologic features. A variety of FDC markers is required to confirm their origin as the expression of any single marker is not assured, as occurred in this case. Pathologists need be aware of FDC proliferations in HVCD because of their association with FDC sarcoma. Aberrant EGFR expression by dysplastic FDCs may indicate that they are pre‐neoplastic and necessitate long‐term patient follow‐up.     

Cytopathology of follicular dendritic cell tumors

Follicular dendritic cell tumors are rarely described entities, arising from antigen-presenting immune accessory cells, found within B-lymphocyte follicles in nodal and extranodal sites. We report two cases, one associated with Castleman's disease, in whom fine-needle aspiration biopsy was performed followed by surgical biopsy. The diagnosis was confirmed using immunoreactivity with CD21 and CD35 antibodies and by ultrastructural demonstration of interdigitating cell processes with desmosomes. Both the cytologic and histologic findings are presented, and the differential diagnoses are discussed. Awareness of this entity and recognition of the pathologic features may lead to a presumptive diagnosis which must be confirmed using immunohistochemistry and/or electron microscopy. Diagn. Cytopathol. 17:138–142, 1997. © 1997 Wiley-Liss, Inc.     

Interdigitating dendritic cell sarcoma: Clinicopathologic study of 8 cases with review of the literature

To investigate the clinicopathologic features and differential diagnoses of interdigitating dendritic cell sarcoma (IDCS), the clinical, morphological and immunohistochemical features of eight cases of IDCS were collected and analyzed. Three patients were males and five were females, the mean age and the median age were 56.5 years and 57 years respectively. Clinically, the majority of cases involved lymph nodes. Microscopically, neoplastic cells were spindle or ovoid, forming fascicles or whorls. Every case had active mitosis figures. Immunohistochemically, these neoplastic cells were consistently positive for S100, but negative for CD21 and specific B-cell and T-cell associated antigens. Follow-up results were available in 7 cases, of which 5 cases of localized lesions survived, 2 cases died of organ involvement. Interdigitating dendritic cell sarcoma is an extremely rare neoplasm, with inferior prognosis and without standard treatment regimen. IDCS has similar but unique clinicopathologic features and the differential diagnoses include other histiocytic and dendritic cell neoplasms and malignant melanoma.     

Sarcoma of follicular dendritic cells with features of sinus lining cells—a new subtype of reticulum cell sarcoma?

Dendritic cell neoplasms of the World Health Organization classification comprise Langerhans cell histiocytosis, Langerhans cell sarcoma, interdigitating dendritic cell sarcoma, follicular dendritic cell sarcoma, and dendritic cell sarcoma, not otherwise specified. Several studies based on immunohistochemical and ultrastructural analysis tried to further clarify the origin of these neoplasms which are thought to derive from mesenchymal or bone marrow precursors. Lymphatic vessel endothelium hyaluronan receptor-1 (LYVE-1) was recently described as a marker for lymphatic endothelium which is expressed on normal liver blood sinusoid lining cells, spleen endothelium, activated tissue macrophages, blood vessels in the lung, endothelial cells of lymphatic sinuses, and in fibroblastic reticular cells in lymph nodes. We present a case of LYVE-1-positive reticulum cell neoplasm in an axillary lymph node. To the best of our knowledge, there has been no report about LYVE-1 expression in histiocytic or dendritic cell neoplasms so far. Due to the assumed specificity of this antibody, we propose designation of this reticulum cell sarcoma as lymphatic sinus lining cell sarcoma which might finally represent another subtype of reticulum cell sarcomas.     

Interdigitating dendritic cell sarcoma: a report of four paediatric cases and review of the literature

AIMS: To report a series of four paediatric cases of interdigitating dendritic cell sarcoma (IDCS) and add to the known extranodal sites of occurrence for this tumour. Neoplasms derived from interdigitating dendritic cells are rare, with only 33 cases being reported in the literature (Medline search). These tumours usually occur in lymph nodes in the adult population. METHODS AND RESULTS: The patients were a 10-year-old girl with a large soft tissue mass bulging into the left chest, a 12-year-old girl with a right paraspinal mass, a 21-month-old boy with generalized lymphadenopathy and hepatosplenomegaly and a 6-year-old girl with a large bladder mass. Paraffin blocks and haematoxylin and eosin slides were available in all cases. In addition, immunohistochemistry and electron microscopy were performed. A diagnosis of IDCS was made in all cases. CONCLUSION: The diagnosis of IDCS can rarely be entertained on clinical information alone. Microscopically, there is a wide spectrum of features. Thus, immunohistochemistry and electron microscopy are crucial in making the diagnosis. The differential diagnosis includes inflammatory pseudotumour, follicular dendritic cell sarcoma, true histiocytic lymphoma, malignant Langerhans cell histiocytosis, anaplastic large-cell lymphoma, melanoma, and a range of sarcomas. IDCS displays aggressive behaviour and approximately half of the patients die of the disease.     

Non-hematopoietic neoplastic and pseudoneoplastic lesions of the spleen

The spleen can be affected by several different non-hematopoietic neoplasms as well as pseudoneoplastic lesions. Generally such conditions affect asymptomatic adults and are detected only as incidental findings; in a minority of the cases vague, unspecific symptoms including abdominal discomfort can occur. Most of these conditions present as a “solitary splenic mass” and have been traditionally diagnosed on partial or total splenectomy, which also represents the most common therapeutic strategy; however, the increasing use of splenic needle biopsies for such lesions creates new diagnostic challenges for pathologists. Splenic cysts (including true cysts, pseudocysts and parasitic cysts) and hamartomas are common benign proliferations which generally pose little problems in their identification. More challenging is the diagnostic workup of “spindle cell and inflammatory rich” lesions of the spleen, whose correct identification is crucial. Indeed, some of these are considered reactive (such as sclerosing angiomatoid nodular transformation of the spleen), whilst others are clonal in nature, the main example being represented by the so called “inflammatory pseudotumour- like follicular/fibroblastic dendritic cell sarcoma”. A further degree of complexity is represented by the detection of the Epstein-Barr virus (EBV), which is invariably present in inflammatory pseudotumour- like follicular/fibroblastic dendritic cell sarcoma, but also in other proliferations including the rare “EBV- related smooth muscle tumor of the spleen”. Finally, the spleen can host rare dendritic/reticulum cell sarcomas and metastases from extrasplenic malignancies. The current review aims at highlighting the main histologic features of non-hematopoietic and non-vascular neoplasms as well as pseudoneoplastic lesions of the spleen.     

The application of the metalophil method for the demonstration of histiocytes

The metalophil method has been performed on 250 sections of a wide variety of inflammatory and neoplastic lesions in which different types of histiocytes might be encountered. In lymph nodes, dendritic histiocytes related to the B-lymphocyte system were consistently metalophil. They appeared as small cells with slender extensions in lymph nodes with follicular hyperplasia and/or sinus histiocytosis and in some cases of Hodgkin's lymphomas or as larger pleomorphic cells in primary or secondary malignancies of lymph nodes. Small, rounded cells were seen in some cases of marked paracortical reaction, in dermatopathic lymphadenitis and in some cases of mycosis fungoides. These cells most probably represented Langerhans cells and interdigitating reticulum cells, which are related to the T-lymphocyte system. Interdigitating cells become metalophil when they are activated or proliferating. Epithelioid cells in different benign and malignant lesions were metalophil like the sinus histiocytes of the lymph nodes, the Kupffer cells of the liver and the alveolar histiocytes in the lung. Foreign-body giant cells in lymph nodes after lymphography were also metalophil. The sinus lining cells lymph nodes were also well-delineated. Histiocytes of malignant histiocytic proliferations were sometimes metalophil as were the so-called histiocytes in malignant fibrous histiocytomas. Epithelial cells, particularly the basal cells of squamous epithelium often take up the silver. Carcinoma cells were sometimes metalophil and the method appeared not to be of value in the differentiation between metastatic carcinomas and lymphomas. The most promising application seems to be the study of the distribution of dendritic histiocytes in malignant proliferations of B-lymphocytes.     

Interdigitating dendritic reticulum cell sarcoma: cytologic, histologic and immunocytochemical features

Tumors of dendritic reticulum cells are rare neoplasms that exhibit significant morphologic overlap with other malignancies. Fine-needle aspiration cytologic appearances of this neoplasm are not well understood. A 33-yr-old woman presented with a rapidly growing nodular mass in the right upper cervical region and right-sided ptosis. Fine-needle aspiration cytology of the mass showed dissociated as well as clustered, large, polygonal cells that showed high nuclear-cytoplasmic ratio. Nuclei were round, oval, or irregular in shape. Large and small blastoid forms with prominent nucleoli and chromatin clumping as well as binucleated cells and cells with lobulated nuclei were seen. Numerous mitoses were observed. The tumor cells expressed focal immunocytochemical reactivity to CD45 and CD68, but were negative for CD2, CD3, CD4, CD8, CD20, CD30, CD45RO, epithelial membrane antigen (EMA), cytokeratin, and HMB45. Histologic sections of the biopsy from the growth showed nodal tissue effaced by a tumor composed of large, pleomorphic neoplastic cells with some binucleate and multinucleate forms resembling Reed-Sternberg cells. The intervening stroma contained numerous small lymphocytes. Tumor cells expressed vimentin, S-100 protein, CD68, and MAC387, but were negative for LCA, CD1a, CD3, CD15, CD20, CD21, CD23, CD30, CD35, carcino-embryonic antigen, HMB45, cytokeratin AE1/3, EMA, myeloperoxidase, lysozyme, smooth-muscle actin, and desmin. The combined histologic and immunohistologic features suggested a histiocytic/dendritic reticulum cell neoplasm and a diagnosis of interdigitating dendritic reticulum cell sarcoma was made.     

Dendritic cell sarcomas/tumours of the breast: report of two cases

Extranodal follicular dendritic cell sarcoma/tumours (FDCS/Ts) and interdigitating dendritic cell sarcoma/tumours (IDCS/Ts) are rare neoplasms. We present two cases of FDCS/T and IDCS/T of the breast. The FDCS/T case (case 1) presented in a 31-year-old woman and the IDCS/T case (case 2) in a 67-year-old woman who both showed a firm lump in the left breast. The FDCS/T lesion superficially appeared as an anaplastic carcinoma and the IDCS/T was reminiscent of a spindle cell sarcomatoid carcinoma. Nevertheless both lesions were negative for keratins while case 1 displayed neoplastic cells strongly positive for CD21, vimentin and focally for CD68 and S-100 protein. The tumour cells of case 2 were positive for S-100, CD68 and CD45. In breast, an unusual keratin negative tumour composed predominantly of spindle cells arranged in fascicles, storiform pattern or whorls with a lymphoid rich stroma should raise suspicion for FDCS/Ts or IDCS/Ts. The distinction from malignant tumours with similar features is discussed.     

指状树突细胞肉瘤/肿瘤的临床病理观察

目的 探讨指状树突细胞肉瘤/肿瘤(IDCS)的病理特征、诊断及鉴别诊断.方法 分析3例IDCS的临床表现,对标本进行病理形态和免疫组织化学(EnVision法)染色观察.结果 大体检查肿瘤呈灰白、灰黄色,质实.1例发生于左肺,1例原发于脾脏伴全身淋巴结累及,1例发生于淋巴结.光镜下肿瘤组织呈边界不甚清楚的巢片状,部分呈束状、旋涡状排列,周边较多淋巴细胞、浆细胞浸润.肿瘤细胞呈卵圆形或梭形,胞质透亮或轻度嗜酸性,核卵圆形,呈空泡状,可见不明显的小核仁,部分见有核沟.免疫组织化学肿瘤细胞表达S-100蛋白.结论 IDCS是一种罕见的组织细胞和树突细胞恶性肿瘤,有一定的病理学特征.应与滤泡树突细胞肉瘤、炎性假瘤、朗格汉斯细胞组织细胞增生症、恶性黑色素瘤、未分化癌及间变性大细胞淋巴瘤等鉴别.免疫组织化学S-100蛋白等标记对鉴别诊断有帮助.     

Cutaneous epithelioid angiosarcoma: A potential diagnostic trap for cytopathologists

We report on the cytologic features of a rare case of cutaneous epithelioid angiosarcoma of the scalp occurring in a 65-yr-old Chinese male. The prominent epithelioid features may cytologically mimic poorly-differentiated carcinoma, malignant melanoma, and even epithelioid sarcoma. Recognition of subtle cytologic features of vasoproliferation, immunohistochemical demonstration of endothelial markers, and ultrastructural examination are necessary before a final conclusion may be drawn. Diagn. Cytopathol. 16:160–167, 1997. © 1997 Wiley-Liss, Inc.     

Distinction between bronchioloalveolar carcinoma and hyperplastic pulmonary proliferations: A cytologic and morphometric analysis

The objectives of this study were to identify key cytologic features for the morphologic differentiation of bronchioloalveolar carcinoma from reactive pulmonary proliferations, and to determine if morphometry of the cytologic specimens could provide additional data to distinguish the two processes. We analyzed 15 morphologic criteria in pulmonary cytologic specimens from 17 histologically proven cases of bronchioloalveolar carcinoma and 13 cases with reactive cellular changes and compared the findings using univariate analysis. This revealed four statistically significant features more commonly associated with bronchioloalveolar carcinoma: (i) predominance of two- and three-dimensional tissue fragments, (ii) tenacious intercytoplasmic connections between cells, (iii) intranuclear cytoplasmic inclusions, and (iv) paucity of multinucleated cellular forms. Morphometric measurement revealed significant differences between the mean of the nuclear area of benign reactive cells and that of the malignant cells. The utilization of these criteria is helpful to diagnose bronchioloalveolar carcinoma and to distinguish it from reactive pulmonary processes. Diagn. Cytopathol. 16:396–401, 1997. © 1997 Wiley-Liss, Inc.     

Cytologic features of post-transplant lymphoproliferative disorder

Post-transplant lymphoproliferative disorders (PTLD) are Epstein-Barr virus (EBV)–associated lymphoid proliferations which affect approximately 2% of organ allograft recipients. Although the histologic features of PTLD are well described, they have been described only rarely in cytologic specimens. The cytomorphologic features of PTLD in body fluid specimens, needle aspirations, and a gastric brushing specimen from seven patients with histologically confirmed PTLD were therefore reviewed. In the cytologic specimens, PTLD was characterized by a mostly polymorphous population of lymphoid cells containing many large transformed lymphocytes, occasional immunoblast-like atypical lymphocytes, necrosis, and, frequently, obvious plasmacytoid differentiation. The presence of EBV was documented in five of the seven cases in the corresponding tissue biopsies. The four patients with PTLD in a body fluid specimen all died within 3 months of detection of the PTLD in the body fluid. The three remaining patients are alive with resolution of PTLD (follow-up of 7, 8, and 14 months). The diagnosis of PTLD should be suggested when cytologic specimens from organ allograft recipients show a polymorphous atypical lymphoid proliferation, frequently with plasmacytoid differentiation and necrosis. Cytologic samples may provide the initial diagnosis of this potentially fatal disease and allow appropriate intervention. The presence of PTLD in a body fluid specimen is a poor prognostic indicator. Diagn. Cytopathol. 16:489–496, 1997. © 1997 Wiley-Liss, Inc.     

Characterization of distal lymphoid nodules in the chicken caecum

In this report, we describe lymphoid nodules consistently found in the distal region of each chicken caecum at approximately 3 cm from the ileo-cecal junction. These structures were studied by light microscopy both in normal and Eimeria tenella-infected chickens. They were observed with the naked eye in infected birds but not in normal chickens. In these latter the region of the caecal lamina propria corresponding to that in which the lymphoid aggregates were visible revealed a light infiltration by diffuse lymphoid tissue as well as a few germinal centers. The distal lymphoid nodules were studied using a panel of monoclonal antibodies which are specific for chicken Ig-containing cells, macophages, Ia-like positive cells, and interdigitating cells, as well as a policlonal antiserum reactive with S-100 protein to stain both interdigitating cells and follicular dendritic cells. The immunohistochemical study demonstrated the resemblance of these aggregates to the caecal tonsils, suggesting that they represent specialized mucosa-associated lymphoid tissue that respond to antigens in the caecal lumen, their function being to enhance the mucosal defense provided by the caecal tonsils against antigens in the lumen of the caeca. © 1993 Wiley-Liss, Inc.     

Cytological features of inflammatory pseudotumor‐like follicular dendritic cell sarcoma of spleen: A case report

Here, we present the first cytological report of a primary splenic inflammatory pseudotumor‐like follicular dendritic cell sarcoma. The 57 year‐old male was incidentally found with a 2.2 cm well‐demarcated splenic nodule. A sonography guided fine needle aspiration of the lesion was performed. The cytologic smears revealed loosely cohesive fragments of oval to spindle cells in a background of prominent lymphoplasmacytic infiltration. The cells showed sparse chromatin, distinct nucleoli, syncytial cell borders, and occasional cytoplasmic processes. On the liquid‐based preparation, several histiocyte‐like cells with emperipolesis phenomenon were noted. Scant large atypical cells with prominent, cherry‐red nucleoli were found on the cell block sections. The initial cytologic interpretation was “atypical cells cannot exclude classical Hodgkin lymphoma.” The subsequent partial splenectomy showed an inflammatory pseudotumor‐like follicular dendritic cell sarcoma. The tumor cells were positive for CD21, CD35, smooth muscle actin, and EBER in situ hybridization. The cytologic differential diagnoses are briefly discussed. The knowledge of this rare entity, awareness of its cytomorphology, and proper ancillary tests would be helpful for correct cytologic diagnosis. Diagn. Cytopathol. 2017;45:230–234. © 2016 Wiley Periodicals, Inc.     

Interdigitating cell sarcoma: A morphologic and immunologic study of lymph node lesions in four cases

lnterdigitating cell sarcoma is an extremely rare tumor. Its presentation and histologic appearance has varied among the reported cases. In this study, the authors investigated four cases of the hematolymphoid malignancy arising within lymph nodes, which were considered to be of interdigitating cell origin. All patients presented in the 6th to 8th decade of life with peripheral lymphadenopathy, and had a relatively indolent clinical course, without bone marrow or skin involvement. Carcinomas were observed as a second neoplasm in two of four patients. Distinctive morphologic features are proliferation of histiocyte-like cells with nuclear pleomorphism and occasionally multinucleated, paracortical distribution sparing of B-cell regions, fibrosis, sinus infiltration, and a prominent eosinophi/plasma cell infiltrates. The combination of light microscopic, fine structural, and immu-nohistochemical features suggested that these tumors derive from interdigitating cells: these tumor cells expressed CD68 (KP1), S-100 protein and HLA-DR, but lack CD21 (1F8), desmosomes and Birbeck granules. The diagnosis of interdigitating cell sarcoma should be considered on any pleo-morphic tumor with the features described in this report.     

Ultrastructural characteristics of the interdigitating dendritic cell in dermatopathic lymphadenopathy of mycosis fungoides patients

The ultrastructure of interdigitating dendritic cells in dermatopathic lymphadenopathy from patients with mycosis fungoides was investigated. The most remarkable findings were: a marked hypertrophy of the smooth endoplasmic reticulum with a peculiar concentric arrangements of the cisternae around lipid droplets, an abundance of cytoplasmic lipid droplets and the presence of paranuclear chromatoid-like bodies. It is suggested that these ultrastructural features may correspond to some unknown functional capability of the interdigitating dendritic cell.