Inflammatory pseudotumor‐like follicular dendritic cell sarcoma of the spleen: A report of six cases with increased IgG4‐positive plasma cells

Inflammatory pseudotumor (IPT)‐like follicular dendritic cell (FDC) sarcoma is a rare neoplasm typically occurring in the spleen or liver. We present six cases of EBV⁺ IPT‐like FDC sarcoma of the spleen among Koreans along with their clinicopathologic features and IHC results. Most patients presented with an asymptomatic, incidentally detected single splenic mass and were successfully managed by splenectomy alone. Concomitant disease was found in one case, showing EBV⁺ gastric carcinoma with lymphoid‐rich stroma. Histologic features showed fibro‐inflammatory lesions that were often accompanied by necrosis and epithelioid histiocytic collection, which are barely distinguishable from IPT. Tumor cells did not frequently express conventional FDC markers, including CD21 (3/6 positive cases), clusterin (4/6), and D2‐40 (2/6), but showed uniform positivity for smooth muscle actin (SMA). Noticeably, significant numbers of IgG4⁺ plasma cells were found within all six tumors. We suggest that the diagnosis of IPT‐like FDC sarcoma should be made by the application of a panel of FDC markers, and CD21 negativity or SMA positivity cannot be the criterion for exclusion of IPT‐like FDC sarcoma. Relationship of IPT‐like FDC sarcoma of the spleen and IgG4‐related sclerosing disease should be investigated in further studies.     

Fine-needle aspiration cytology of a liver metastasis of follicular dendritic cell sarcoma

Follicular dendritic cell sarcoma (FDCS) is an uncommon neoplasm derived from FDCs in lymphoid tissue. Metastatic FDCS to the liver is rare. We present a case of a 65-yr-old woman who was referred to our institution 1 mo after splenectomy for FDCS of the spleen. An abdominal CT scan revealed a 2.0-cm liver lesion, which led to fine-needle aspiration (FNA) biopsy. Smears of the aspiration obtained were hypercellular showing a pleomorphic population of large oval to spindle-shaped tumor cells against a background of small mature lymphocytes, plasma cells, and necrotic debris. Tumor cells were arranged singly, in syncytial or fascicular patterns, and had a moderate amount of cytoplasm and indistinct cell borders. Nuclei had irregular nuclear membranes, finely granular to vesicular chromatin, and prominent nucleoli. Multinucleated and binucleated cells resembling Reed-Sternberg cells were noted occasionally. Mitotic figures, including atypical forms, were frequently identified. The diagnosis of "pleomorphic malignant spindle-cell neoplasm consistent with metastatic FDCS" was rendered and later confirmed by histological review and immunohistochemical staining of the subsequent liver resection specimen. Although cytological features of FDCS are characteristic, they are overlapping with those of many other tumors. We review the literature on this entity with emphasis on FNA cytomorphology, differential diagnosis, and immunohistochemical findings.     

Clinicopathologic characteristics of inflammatory pseudotumor-like follicular dendritic cell sarcoma

Inflammatory pseudotumor (IPT)-like follicular dendritic cell (FDC) sarcoma is a recently described rare tumor and considered a unique entity, with different histologic appearances and behavior from those of the classical FDC sarcoma. This study analyzed the clinical and pathological findings of two such cases that the authors encountered and 36 previously reported cases identified in the literature. Assessment of all 38 cases showed a slight female predominance (2.2:1) with a median age of 56.5 years. Seventeen patients complained of abdominal discomfort or pain, while fifteen patients had no clinical symptom. Almost all cases occurred in liver (n = 20) or spleen (n = 17). Except in one case, all patients underwent surgical resection of the tumor alone. Histologic features showed a mixture of chronic inflammatory cells and variable amounts of spindle cells with vesicular nuclei and distinct nucleoli. The tumor cells expressed conventional FDC markers such as CD21 (75%), CD35 (92%), CD23 (62%), clusterin (75%), and CNA.42 (100%). EBV was detected in thirty-five cases (92.1%) by Epstein-Barr virus (EBV)-encoded RNA in situ hybridization, and EBV-latent membrane protein-1 was expressed in 90% of the cases. With a median follow-up of 21 months, 29 patients (85.3%) were alive and well, 4 (11.8%) were alive with disease, one patient (2.9%) died of disease. Only four patients with hepatic tumors underwent recurrence or metastasis after initial treatment. Epstein-Barr virus is thought to play a role in the development of the tumor; however, the pathogenesis of the disease and the origin of tumor cells remain unclear.     

Interdigitating dendritic reticulum cell tumor of lymph nodes: case report with differential diagnostic considerations

A 66-yr-old man with a history of interdigitating reticulum cell tumor (IDRCT) presented with an enlarging right cervical lymph node suspicious of recurrent disease. He reported no fevers or night sweats and was otherwise asymptomatic at the time of the fine-needle aspiration (FNA). FNA of the lymph node showed a spindle cell lesion with plump, at times deeply convoluted, large nuclei, coarsely granular chromatin, with one or two distinct nucleoli, intimately associated with mature-appearing lymphocytes. A cell block was made and immunohistochemistry was carried out. Immunopositivity for vimentin, S-100, and CD68 and immunonegativity for CD21 and AE1/AE3 were noted. This case report is the first to illustrate the FNA cytomorphology of IDRCT and to discuss the cytologic differential diagnosis of this rare tumor type in lymph nodes.     

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.     

Inflammatory pseudotumor of the spleen: A rare case diagnosed on FNAC

Inflammatory pseudotumor (IPT) is a rare space‐occupying lesion of unknown etiology that can mimic malignancy on clinic‐radiological and pathological examination. We present a case of IPT of the spleen which was clinically suspected to be malignant. This case was initially suggested accurately on fine needle aspiration (FNA) of the mass and subsequently confirmed on histopathology of the resected specimen. Diagn. Cytopathol. 2012. © 2011 Wiley Periodicals, Inc.     

Cytological findings of langerhans cell sarcoma in a case of quintuple cancer

Langerhans cell sarcoma (LCS) and quintuple cancers are extremely rare. In this report, a case of quintuple cancers including LCS was described. An 80‐year‐old man had squamous cell carcinoma of the nasal skin, colon and rectum adenocarcinomas, and T‐cell/histiocyte‐rich large B‐cell lymphoma. As swelling of multiple submental lymph nodes was observed, fine‐needle aspiration was carried out. Many large cells with high‐grade nuclear atypia and abundant cytoplasm were observed. Lymphocytes and eosinophils were observed in the background. Although a malignant tumor was suspected, a definite diagnosis could not be made. In a biopsy sample, the tumor cells were positive for vimentin, CD68, S‐100, CD1a, and CD163 and negative for epithelial, lymphocyte, and melanoma markers in immunohistochemistry. A diagnosis of LCS was made from the immunohistochemical findings and high mitotic rate with atypical forms. The patient died about 2 months after the first medical examination. Metastasis of LCS was confirmed in many organs by autopsy. LCS has a poor prognosis. In cases with the above‐described cytological findings, LCS should be added to the list of differential diagnosis. The cytological findings presented here may be useful for determining appropriate clinical management such as staging of the disease and follow‐up of the neoplasm. Diagn. Cytopathol. 2017;45:441–445. © 2017 The Authors Diagnostic Cytopathology Published by Wiley Periodicals, Inc.     

Cytopathology of a primary follicular dendritic cell sarcoma of the liver of the inflammatory pseudotumor-like type

Follicular dendritic cell (FDC) sarcoma is an exceedingly uncommon tumor of lymph nodes and extranodal tissues. The inflammatory pseudotumor (IPT)-like variant of FDC sarcoma of intraabdominal location is considered a separate entity, with different clinical and pathological features than those of the classic FDC tumor. There have been only 12 cytological reports of FDC sarcomas in the literature. Two of them were metastases to the liver and, like our case, had features of IPT. Fine-needle aspiration biopsy (FNAB) and imprint and scrape cytology from the surgically excised tumor here reported revealed spindle tumor cells with moderate pleomorphism, nuclear grooves, prominent nucleoli, and cytoplasmic processes, admixed with inflammatory cells. To the best of our knowledge, this is the first cytology report of a primary hepatic FDC tumor. The cytological findings permit the recognition of this tumor. However, confirmation by inmunohistochemistry (IHQ) is mandatory for a definitive diagnosis.     

Intrapancreatic accessory spleen: A case report and review of literature

Intrapancreatic accessory spleen is not an uncommon entity and usually located in the tail of the pancreas. Most of them are asymptomatic and incidental findings on radiologic study or at autopsy. On imaging study, it appears to be a well‐defined, solitary, and hypervascular lesion; therefore, it may be confused with pancreatic neoplasms, such as neuroendocrine neoplasm, well‐differentiated adenocarcinoma, solid pseudopapillary tumor, or metastatic tumor to the pancreas. As such, the diagnostic fine‐needle aspiration biopsy of the lesion may be performed. Several case reports describing cytological features of the lesion have been published in recent years. Among them, the most commonly identified cytological findings are sheets of a heterogeneous population of lymphocytes and prominent traversing blood vessels. Herein, we report an unusual EUS‐FNA case of intrapancreatic accessory spleen. In addition to above previously well‐described cytological features, our case revealed many cells with fine granular chromatin and areas with pseudo rosette‐like architecture, mimicking and engendering the differential diagnosis of pancreatic neuroendocrine tumors. Although cytological findings of our case are rare, they may extend our current knowledge and provide additional differential diagnostic information for this entity. Diagn. Cytopathol. 2013. © 2012 Wiley Periodicals, Inc.     

Paraneoplastic pemphigus associated with follicular dendritic cell sarcoma: report of a case and review of literature

Follicular dendritic cell sarcoma (FDCS) is a rare tumor associated with paraneoplastic pemphigus. It is Blame drenchs auxiliary cell tumor which is derived from the peripheral lymphoid tissues. Throughout the world, several patients of paraneoplastic pemphigus associated follicular dendritic cell sarcoma were reported in the literature, but mostly originated from the neck lymph nodes, and extranodal origin of follicular dendritic sarcoma was rarely reported. Also, so far we have found that the malignant degree of all patients diagnosed with malignant tumors have been reported were low and after combined treatment of surgery, radiotherapy and chemotherapy, most of the prognosis was good. However, here we present a patient of paraneoplastic pemphigus associated with follicular dendritic cell sarcoma origined from outside of the lymph nodes and had high tumor malignant degree for its unclear cell boundaries, obvious atypia and mitoses and the patient’s state became progressively deteriorate after operation.     

肝脏炎性假瘤与炎性假瘤样滤泡树突状细胞肿瘤的病理学诊断

目的探讨肝脏炎性假瘤及肝脏炎性假瘤样滤泡树突状细胞肿瘤的临床病理学特征及诊断、鉴别诊断要点。方法对肝脏炎性假瘤及肝脏炎性假瘤样滤泡树突状细胞肿瘤各1例进行临床病理分析、免疫组织化学染色及EBV-encoded RNA（EBER）原位杂交检测。结果肝脏炎性假瘤的临床症状包括右上腹不适或疼痛、发热、肝肿大、体重减轻等。大体肿瘤呈实性,境界清楚;镜下肿瘤细胞呈梭形,波浪状排列,其间可见大量淋巴细胞及浆细胞浸润以及散在分布的大的多形性细胞。核仁明显。肝脏炎性假瘤样树突状细胞肿瘤的临床症状、影像学表现及镜下表现均与肝脏炎性假瘤十分相似。但肿瘤细胞边界不清,胞质嗜酸性,除R—S样细胞外,还可见到不少形态怪异的巨细胞,且免疫表型CD21、CD35阳性。EBER（EBV—encoded RNA原位杂交）阳性。结论肝脏炎性假瘤样滤泡树突状细胞肿瘤是罕见的肿瘤,诊断时需注意与肝脏梭形细胞肿瘤甚至霍奇金淋巴瘤鉴别,树突状细胞免疫标记CD21、CD35阳性,特别是EBER原位杂交阳性有助于诊断。     

Cytologic diagnosis of thyroid‐like follicular carcinoma of the kidney: A case report

Thyroid‐like follicular carcinoma of the kidney (TLFCK) is a recently described subtype of renal‐cell carcinoma that is not currently included in the World Health Organization classification. Few sporadic case reports and one series have been reported with emphasis on histopathologic features. However, cytological features have not been described in the literature to date. A 34‐year‐old male presented with a renal mass. An intraoperative smear preparation of the tumor revealed a hypercellular smear with cells arranged in sheets without any follicular, papillary, or acinar arrangement. The most striking feature was the presence of acellular eosinophilic material associated with the neoplastic epithelial cells in the background of the smear. Individual tumor cells were oval, round, and plasmacytoid with mild nuclear pleomorphism, finely stippled nuclear chromatin, and inconspicuous nucleoli with moderate amount of eosinophilic cytoplasm and rare nuclear grooves. It was unclear at the time of the intraoperative assessment of the smear if the acellular eosinophilic material represented metachromatic matrix‐like extracellular material, mucin, colloid, amyloid, or hyaline material. The differential diagnoses included a primary renal‐cell carcinoma versus a metastatic tumor. Subsequent histopathologic examination was diagnostic of a rare, recently described primary neoplasm of the kidney called TLFCK. This work is a retrospective evaluation of the cytological features of TLFCK. It is important for cytopathologists to be aware of this entity and its cytological features to render a correct diagnosis for adequate management of these patients. Diagn. Cytopathol. 2014;42:273–277. © 2012 Wiley Periodicals, Inc.     

Alveolar soft part sarcoma: A case report with emphasis on some unusual cytological features

Alveolar soft part sarcoma is a very rare, slow growing highly angiogenic tumor with poor prognosis. Most common site in children and infants is head and neck region and in adults it most commonly occurs in extremities especially thigh. In our case study, an 8 years old female patient presented with a gradually progressive left shoulder lump. FNAC from the lesion showed cellular smears with polyhedral and spindly cells showing abundant finely vacuolated cytoplasm, nuclear pleomorphism, intranuclear pseudoinclusions, and few bare nuclei. Perivascular arrangement of cells was peculiar in addition to the presence of intracytoplasmic metachromatic PAS positive diastase resistant granules. A presumptive diagnosis of alveolar soft part sarcoma with differentials of granular cell tumor and PEComa was considered and the lesion was excised. Although the histopathological features were not characteristic (ie, showing mainly solid pattern without classic alveolar pattern), immunohistochemistry were diagnostic (negative for S 100, Desmin, Cytokeratin, EMA, and moderate to strong nuclear positivity for TFE3). Thus, the diagnosis of alveolar soft part sarcoma was established. This case is being presented for its rarity and unique cytological and histopathological features.     

Cytological findings of monophasic synovial sarcoma presenting as a lung mass: report of a case and review of the literature

Synovial sarcomas are rare malignant mesenchymal tumors that can arise from any anatomic site. Although they are often located at the paraarticular region of the extremities, the incidence of synovial sarcomas in the lungs is rare, with only a few cytology case reports to date. We report a case of synovial sarcoma presenting as a lung mass diagnosed on fine‐needle aspiration (FNA) cytology. The patient is a 38‐year‐old chronic smoker who presented with cough, worsening dyspnea, and weight loss. Computerized tomography of his chest revealed an 8‐cm left lower lobe pleural‐based mass. An FNA of the lung mass showed cellular smears composed of monotonous population of singly scattered to sheets of bland spindle cells with elongated nuclei, fine chromatin pattern, and scant to moderate amount of delicate cytoplasm. Immunohistochemical stains performed on the cell block showed that the tumor cells were positive for calretinin and focally positive for pancytokeratin, CAM5.2, and smooth muscle myosin heavy chain. The tumor cells were negative for S‐100, podoplanin, and CD34. Fluorescence in situ hybridization performed on the cell block demonstrated the presence of SYT (18q11) translocation, supporting the diagnosis of synovial sarcoma.     

Fine‐needle‐aspiration cytology of a proximal type epithelioid sarcoma: A case report

Epithelioid sarcoma is a rare mesenchymal neoplasm, with an as yet unidentified cell of origin. Two subtypes of epithelioid sarcoma, distal/classic and proximal/large cell type, are recognized in the literature; with the proximal‐type having a lower incidence amongst the two. Here, we present a case of proximal‐type epithelioid sarcoma in a previously healthy young man. Fine‐needle‐aspiration of a large axillary mass was performed for diagnosis. The cytologic findings included a dispersed population of large epithelioid to polyhedral cells with abundant cytoplasm. Immunohistochemical staining showed coexpression of keratin and vimentin, as well as loss of INI1 staining, consistent with an epithelioid sarcoma, proximal subtype. Diagn. Cytopathol. 2015;43:859–862. © 2015 Wiley Periodicals, Inc.