Inflammatory pseudotumor of the spleen. Report of a case with an immunohistochemical study.

A 81-year-old Japanese man with a splenic inflammatory pseudotumor is described. The pseudotumor was unchanged in size after one year of observation. Macroscopically, the lesion was a firm well-circumscribed 5.5 x 5 x 5 cm mass showing a yellowish-white cut surface. Histologically, it was composed of abundant mixed inflammatory infiltrates, predominantly UCHL-1(+) T and L26(+) B lymphocytes, plasma cells containing various immunoglobulin subtypes, and S-100 protein(+), and lysozyme and NCA(+) histiocytes, with a sclerotic stroma. Small numbers of eosinophils, neutrophils and foamy macrophages were admixed. The patient has remained disease-free for 14 months after splenectomy. Only ten splenic inflammatory pseudotumors have been reported in the literature. This paper adds an additional case, together with details of immunohistochemical polyclonality of each inflammatory cell population, confirming that this disease is a nonspecific inflammatory change.     

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.     

IgG4-associated inflammatory pseudotumor of ureter: clinicopathologic and immunohistochemical study of 3 cases

Inflammatory pseudotumors are lesions characterized by proliferation of fibroblasts/myofibroblasts with variable chronic inflammatory cell infiltration. Recent studies have suggested that inflammatory pseudotumor with abundant IgG4-positive plasma cells may be a unique entity associated with systemic IgG4-related sclerosing disease and should be distinguished from other similar lesions such as inflammatory myofibroblastic tumor and fibrohistiocytic-type inflammatory pseudotumor. Localized inflammatory pseudotumor has been rarely reported in the ureter, and IgG4-associated inflammatory pseudotumor of ureter has not been described. We describe herein 3 cases of ureteral inflammatory pseudotumor of IgG4-associated lymphoplasmacytic type, focusing on density of IgG4-positive plasma cells; infiltration pattern of eosinophils and histiocytes; presence of obliterative phlebitis; and immunohistochemical profiles of smooth muscle actin, anaplastic lymphoma kinase, and CD68. Three patients, 45- and 47-year-old men and 84-year-old woman, all presented with flank pain and ureteral narrowing by a mass effect. Microscopic examination of the resected ureters showed suburothelial masslike lesions with fibroblasts/myofibroblasts without atypia, abundant plasma cells, and scattered eosinophils and histiocytes. The lesion of the 47-year-old man showed obliterative phlebitis in addition to the above findings. The lesion of the 84-year-old woman was accompanied by urothelial carcinoma in situ in the overlying urothelium. Spindle cells were diffusely or focally positive for smooth muscle actin but negative for anaplastic lymphoma kinase in all 3 cases. For each case, respectively, an average of 154, 112, and 50 plasma cells per high-power fields were immunoreactive for IgG4, a diagnostic feature of IgG4 inflammatory pseudotumor. We described 3 cases of IgG4-associated inflammatory pseudotumor of ureter with pathologic and immunohistochemical features that are compatible for lymphoplasmacytic type of inflammatory pseudotumor. Further study is needed to characterize any relationship between this entity and systemic sclerosing disease and/or urothelial carcinogenesis.     

Inflammatory pseudotumor of the urinary bladder with an aberrant expression of cytokeratin

A case of inflammatory pseudotumor of the urinary bladder in a 47 year old Japanese male patient is presented. Inflammatory pseudotumor of the urinary bladder is a benign but rare proliferative lesion of the submucosal stroma, easily mistaken for a malignant neoplasm. Based on the clinical diagnosis of bladder cancer by cystoscopy and magnetic resonance imaging (MRI), urologists started chemotherapy before results of the histological report were available which described inflammatory pseudotumor on the biopsy. Biopsied materials showed marked proliferation of irregularly bundled spindle ceils, varied in size and shape and separated in severe loose myxoid stroma with moderate infiltration of the inflammatory cells and capillary proliferations. At a glance, these findings resemble the sarcomatous pattern. However neither severe nuclear atypism nor atypical mitoses were present. Immunohistochemically, these spindle cells, which were positive for vimentin and α-smooth muscle actin, showed a diffuse aberrant expression of cytokeratin. Some of them were positive for phosphotungstic acid hematoxylin. Electron microscopy revealed only the fibroblasts. No recurrence has been observed for 10 months. These findings indicate that inflammatory pseudotumor is a benign mesenchymal lesion that must be discriminated from true sarcoma to avoid subjecting the patient to unnecessary therapy. Only careful histological examination can enable a successful diagnosis.     

小于2cm肺内炎性假瘤的HRCT诊断

目的 探讨肺内2cm以下炎性假瘤的高分辨率CT（HRCT）表现。方法 24例经手术或穿刺活检病理证实的肺内直径2cm以下炎性假瘤的患者行HRCT检查，其中16例同时行增强扫描。结果 24例中，出现浅分叶征8例，棘状突起6例，晕征8例，血管集束征5例，空泡征1例；增强扫描16例，其中6例有轻度强化，10例无明显强化。所有病灶边缘均较光整。结论 HRCT在诊断肺内小于2cm炎性假瘤有很大价值，各种征象综合分析可提高诊断的正确性。     

Inflammatory pseudotumor of the spleen. Report of two cases with a review of the literature

This study reports two cases of inflammatory pseudotumor of the spleen. The first case was a 57-year-old woman in whom the splenic mass was an incidental finding during evaluation for an acute abdomen due to a perforated, lithiasic gallbladder. The mass in the spleen measured 12.7 cm in greatest dimension. The second case was of a 46-year-old woman with a palpable, left upper quadrant mass. A computed tomography scan revealed a splenic mass and the spleen was removed. The mass measured 12 cm in greatest dimension. In a review of the literature, 13 examples of splenic inflammatory pseudotumor were reported. The age range was 19 to 75 years, with a median age of 50 years. The splenic lesions were either discovered incidentally or manifested by left upper quadrant discomfort and/or mass. Inflammatory pseudotumor of the spleen, although rare, is being increasingly recognized and should be considered in the differential diagnosis of mass lesions of the spleen.     

Hypophysitis presented as inflammatory pseudotumor in immunoglobulin G4-related systemic disease

Immunoglobulin (Ig) G4-related systemic disease is a recently characterized entity. The best-known manifestation is pancreatitis. Other systemic involvements are also described. Three cases of this disease with hypophyseal involvement have been reported in the literature, all diagnosed clinically. We herein present the first case of IgG4-related hypophysitis diagnosed histopathologically. The patient is a 77-year-old Chinese man with a pituitary tumor. Histologic examination of the resected tumor showed hypophysitis with features of inflammatory pseudotumor. Clinical review showed history of pancreatitis and cholecystitis 4 years ago. The pancreatic biopsy and gall bladder specimens obtained previously had the same pathologic features of inflammatory pseudotumor. Immunohistochemistry highlighted abundant IgG4-positive plasma cells in all 3 specimens. Serum IgG4 level was also elevated. A diagnosis of IgG4-related systemic disease was confirmed. This is the first case of intracranial inflammatory pseudotumor shown to be associated with IgG4-related systemic disease.     

Transthoracic fine-needle aspiration cytology of inflammatory pseudotumor,fibrohistiocytic type: A case report with immunohistochemical studies

Inflammatory pseudotumor, fibrohistiocytic type, also called benign fibrous histiocytoma, is a rare reactive entity usually found incidentally on routine chest roentgenography. We present a case of inflammatory pseudotumor, fibrohistiocytic type, initially diagnosed by fine-needle aspiration (FNA) cytology in a 39-yr-old woman with a history of breast carcinoma. Cytomorphologic characteristics were confirmed by a cell block examination and immunohistochemical findings. The differential diagnoses of the fine-needle aspiration cytology of this type of inflammatory pseudotumor are discussed. Diagn. Cytopathol. 1998:19:216—220. © 1998 Wiley-Liss, Inc.     

A case of pseudolymphoma of the liver

A case of pseudolymphoma (reactive lymphoid hyperplasia) of the liver in a 66 year old female is presented. A tumor-like lesion was incidentally discovered in the liver during clinical follow up of diabetes mellitus. The hepatic lesion was resected because malignant lymphoma was suspected after a needle biopsy. Grossly, the lesion was well-deflned and measured 1.0 × 1.5 × 1.0 cm. Microscoplcally, the lesion consisted of hyperplastic lymphoid follicles with distinctive germinal centers and interfollicular areas consisting of mature lymphocytes and plasma cells. An immunohistologlcal study revealed that the lymphoid cells of the lesion were polyclonal in immunophenotypes. These histological and immunohistochemical findings strongly suggested a pseudolymphoma and not hepatic inflammatory pseudotumor. Thls case was diagnosed as pseudolymphoma of liver. Only a few cases of hepatic pseudolymphoma have so far been reported In the English literature.     

Inflammatory pseudotumor of the spleen: two case reports

Inflammatory pseudotumor (IPT) of the spleen is an uncommon entity with debated etiology, characterized by a mixture of inflammatory cells and a component of myofibroblastic spindle cells. This lesion needs to be distinguished from the follicular dendritic cell tumor and the inflammatory myofibroblastic tumor. We report two cases of splenic PTI in a 69-year old and a 62-year old women. The tumors measured respectively 80 and 30 mn in greatest dimension. An inflammatory pseudotumor was histopathologically diagnosed following a splenectomy.     

艾滋病患者CMV感染致消化道假瘤5例临床病理分析

目的探讨艾滋病(acquired immune deficiency syndrome, AIDS)患者巨细胞病毒(cytomegalovirus, CMV)感染导致消化道假瘤的临床病理特征、诊断与鉴别诊断。方法 5例患者均经内镜活检,采用HE、免疫组化染色,计数CD4阳性细胞,分析AIDS患者CMV感染致消化道假瘤的临床病理特征、免疫表型,并复习相关文献。结果 5例患者临床均表现为溃疡型肿物,镜下未见肿瘤细胞,可见黏膜水肿、坏死、炎症及溃疡形成,其间大量炎性肉芽组织、纤维血管组织增生或肉芽肿形成,导致局部形成肿块或假瘤样表现;可见病毒包涵体,形成"鹰眼"样征象,部分包涵体形态不典型;CMV经免疫组化染色可以更好地显示病毒包涵体。有3例患者外周血CMV-DNA水平增高;5例患者外周血CD4⁺T淋巴细胞计数1~72个/μL;5例患者消化道黏膜CD4⁺T淋巴细胞阳性标记指数为1.53%±1.27%,稍低于AIDS非特异性病变患者(3.6%±0.47%)(P<0.01);显著低于无免疫缺陷患者(27.8%±4.6%)(P<0.01)。结论在AIDS或免疫缺陷患者中出现消化道肿瘤特别是内镜下提示为溃疡型肿瘤,伴血CMV-DNA水平升高(也可正常)及CD4⁺T淋巴细胞明显减少(细胞计数<100个/μL)时,需警惕CMV感染的可能,临床与病理医师应重视内镜下活检,并行HE及免疫组化染色或行原位杂交检测。     

Immunohistological Studies of Fibrous Pseudotumor of the Testicular Tunica Vaginalis

A fibrous pseudotumor of the testis from a 46 year old man was examined histologically and immunohisto-chemically. The tumor, situated in the tunica vaginalis, appeared as multiple round nodules up to 2 cm in diameter, and was composed largely of fibrous tissue with scanty inflammatory cell infiltration. Besides mesothelial cells covering part of the tumor, foci of piled up cells were found among the fibrous tumor tissue. The cells in the foci were spindle and polygonal in shape, and contained oval nuclei. Immunohistochemically, these cells were positive for vimentin and keratin, but negative for CEA. Similar features have been found in pleural mesothelioma, supporting the concept that testicular fibrous pseudotumor could represent neoplastic growth of the mesothelium of the tunica vaginalis. Acta Pathol Jpn 39: 810813, 1989.     

Inflammatory pseudotumor of the liver in a patient with chronic hepatitis C: Difficulty in differentiating it from hepatocellular carcinoma

A case of an inflammatory pseudotumor of the liver in a 75-year-old female with chronic hepatitis C whose radiologic features simulated that of hepatocellular carcinoma (HCC) is presented. On imaging studies, hypervascularity by CO2 ultrasound (US) angiography, enhancement at an early phase and isodensity at a late phase by incremental dynamic computed tomography (CT), perfusion defect by CT during arteriography (CTAP), and clinical background of hepatitis C virus (HCV) infection strongly suggested HCC. A US-guided needle biopsy revealed a mainly diffuse and polyclonal proliferation of lymphocytes positive for leukocyte common antigen (pan-lymphocyte cells), L-26 (B cell lymphocytes), and UCHL-1 (T cell lymphocytes), negative for both kappa and lambda light chains and sparsely distributed neutrophils and histiocytes. No lymphoid follicles were observed. The liver tissue around this tumor showed chronic hepatitis with mild activity and mild fibrosis. These histopathologic findings suggested that the diagnosis of inflammatory pseudotumor of the liver was tenable. As it is difficult to differentiate between inflammatory pseudotumor of the liver and HCC by imaging studies alone, supplemental biopsy, where possible, should be obtained when diagnostic imaging of tumors suggesting HCC is carried out. We emphasize that histopathology is a true gold standard in the diagnosis of this disease.     

肺粘膜相关型淋巴瘤与肺炎性假瘤临床病理及免疫组化研究

目的 :探讨肺粘膜相关型淋巴瘤和肺炎性假瘤的病理特征及相互关系。方法 :对 9例肺粘膜相关型淋巴瘤和 6例肺炎性假瘤进行临床病理及免疫组化研究。结果 :男性多见 ,平均年龄 5 8岁 ,干咳、胸闷、胸痛为主要症状。病理形态 :肺粘膜相关型淋巴瘤 9例 ,细胞类型 ,CCL细胞性 6例、小淋巴细胞性 2例 ,淋巴浆细胞性 1例。肺炎性假瘤 6例。免疫组化证实 ,肺粘膜相关型淋巴瘤 9例LCA 、L2 6 、IgM、κ或λ呈单克隆性 ,6例炎性假瘤显示多克隆性。 结论 :两者临床鉴别困难 ,病理诊断须依靠免疫组化才能鉴别 ,两者均应以手术治疗为主。     

Inflammatory pseudotumor of lymph node and spleen: An entity biologically distinct from inflammatory myofibroblastic tumor

Inflammatory pseudotumors (IPTs) of the lymph node and spleen are an uncommon, benign cause of lymphadenopathy and/or splenomegaly that often bear striking clinicopathologic similarities to the inflammatory myofibroblastic tumors (IMTs) found in soft tissues. These tumors have classically been grouped together under the umbrella category of "inflammatory pseudotumor." Recent evidence shows that IMTs are in fact neoplastic processes that often harbor balanced chromosomal translocations involving the ALK kinase gene. These translocations result in expression of ALK kinase in IMTs as assessed by immunohistochemical studies. However, the relationship between IMT and IPT of the lymph node and spleen is uncertain. To determine if ALK tyrosine kinase expression is also present in IPT, 13 cases of IPT (9 involving lymph nodes, 4 splenic lesions) were examined for the presence of ALK tyrosine kinase by immunohistochemical staining on paraffin-embedded tissue. In addition, in situ hybridization studies for Epstein-Barr virus--encoded RNAs (EBER) and immunoperoxidase studies for human herpesvirus-8 (HHV8)--specific proteins were performed. All cases had clinical, morphologic, and immunophenotypic findings typical of IPT and had varying proportions of fibroblastic and inflammatory components. Age ranged from 11 to 75 (median, 40) years; 8 subjects were male, and 5 were female. None of the cases (0 of 13) had positive staining for ALK kinase or HHV8, and in 1 a lymph node (1 of 13) was focally positive for EBV (EBER) by in situ hybridization. The absence of ALK kinase as detected by immunohistochemical studies in IPT of the lymph node and spleen suggests that this entity is biologically distinct from the histologically similar IMT.     

Transthoracic needle aspiration biopsy in inflammatory pseudotumors of the lung

The cytologic findings on transthoracic needle aspiration biopsy in four patients with pulmonary inflammatory pseudotumor are described. These findings have not been previously illustrated in the literature. The main cytologic components of this lesion are histiocytes, lymphocytes, fibroblasts, pneumocytes, and plasma cells. Familiarity with these features is essential to avoid misdiagnosis and possible overtreatment.     

Postoperative spindle-cell nodule of urinary bladder with unusual intracytoplasmic inclusions.

Postoperative spindle-cell nodule of the urinary bladder (or in the absence of previous surgical procedure, inflammatory pseudotumor) is a reactive process of unknown etiology mimicking a sarcoma. Intracytoplasmic inclusion bodies were noted inside the atypical spindle cells on Diff-Quik stained smears in a recent case of this entity. Although fluorescence was noted in the inclusion bodies with monoclonal antibodies against the major outer membrane protein of the Chlamydia species, the exact nature of these inclusion bodies remains unknown.     

Splenic inflammatory myofibroblastic tumor (inflammatory pseudotumor): a clinicopathologic and immunophenotypic study of 12 cases

CONTEXT: Inflammatory pseudotumor is an uncommon and enigmatic lesion. The spindle cells found in this tumor have features of myofibroblasts. Because of the indefinite relationship of these lesions with inflammatory fibrosarcoma and their indefinite biologic behavior, inflammatory pseudotumor is currently classified as inflammatory myofibroblastic tumor (IMT). To date, only case reports or small series have been published on these tumors, which are primary in the spleen. DESIGN: In this study, we describe the clinical, morphologic, and immunophenotypic findings of 12 cases of splenic IMT and examine their relationship to Epstein-Barr virus (EBV). RESULTS: The patients included 8 women and 3 men, ranging from 19 to 77 years of age (mean, 53 years; median, 60 years). Demographic data were unavailable for 1 patient. Patients generally presented with abdominal pain (n = 5) and fever (n = 4). Associated lesions included renal cell carcinoma (n = 2), colonic adenocarcinoma (n = 1), and cholecystitis (n = 1). All tumors were composed of a bland spindle cell proliferation in association with a variable mixed inflammatory component. There were 2 growth patterns, namely, a cellular spindle cell pattern and a hypocellular fibrous pattern. An immunohistochemical panel confirmed the myofibroblastic nature of the spindle cells. The spindle cells of 2 cases were immunoreactive for EBV latent membrane protein 1, whereas 6 of 10 cases were positive for EBV-encoded RNA using in situ hybridization. Follow-up was available for 8 patients; 6 were alive with no evidence of recurrence and 2 were dead of other causes. CONCLUSION: Splenic IMTs are uncommon lesions that can be distinguished from other conditions using a combination of clinical, histologic, and immunophenotypic findings. Epstein-Barr virus may play a role in the pathogenesis of splenic IMT, and there may be an association of splenic IMT with concomitant disease or malignancy. Most splenic IMTs have an excellent long-term prognosis.     

Two splenic lesions in need of clarification: hamartoma and inflammatory pseudotumor

This short review is dedicated to a precise pathologic characterization of 2 uncommon and poorly defined lesions of the spleen and to their distinction from histologically similar processes. Splenic hamartoma represents an abnormally formed red pulp and is characterized by the presence of sinus-like structures lined by CD8(+) endothelia. The great variety of its morphologic appearances may result from the preponderant growth of one or another of the several components of the red pulp, ie, CD34(+) capillaries, myoid cells and macrophages. Therefore, it is proposed that "cord capillary hemangioma," myoid angio-endothelioma, and histiocyte-rich tumors are part of the spectrum of splenic hamartoma. Inflammatory pseudotumor (IPT) of the spleen is a reactive lesion, probably of multiple etiologies, characterized by a mixture of inflammatory cells and a minor, disorganized component of spindle cells. The latter include fibroblasts, SMA(+) myofibroblasts, and CD68(+) spindled histiocytes, establishing a close similarity with the IPT of the lymph node. This benign process needs to be distinguished from 2 others that have a predominant spindle cell component arranged in parallel bundles: the IPT-like follicular dendritic cell tumor, which is consistently associated with Epstein-Barr Virus; and the inflammatory myofibroblastic tumor, also often Epstein-Barr Virus-related and similar to those of the soft tissues, lung and other organs. These 2 lesions are neoplastic and therefore have a potentially worse prognosis than IPT.