Inflammatory pseudotumor of urinary bladder

A previously healthy 44-year-old male was admitted with the chief complaint of intermittent gross hematuria. On initial ultrasonographic and CT examination, a grossly protruding intravesical tumor was noted and, under the impression of a malignant bladder tumor, transurethral resection was performed. The histological findings were spindle cells with elongated cytoplasm with rare mitotic figures distributed in myxoid stroma, consistent with diagnosis of inflammatory pseudotumor of the bladder. The benign nature of this tumor warrants conservative surgical management, usually consisting of transurethral resection or partial cystectomy. No reports of metastasis have been reported following complete excision. Therefore, any suspicion and recognition of this entity is imperative to avoid performing an irreversible radical procedure.     

Inflammatory pseudotumor of the urinary bladder in a child

The inflammatory pseudotumor of the urinary bladder is rare, especially in children. It is a benign proliferative lesion of the submucosal stroma easily mistaken for a sarcoma clinically, so it should be differentiated from a malignant neoplasm. We report the case of bladder inflammatory pseudotumor in a 7-year-old girl.     

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.     

The role of immunohistochemistry in the diagnosis of urinary bladder neoplasms

The spectrum of neoplasms involving the urinary bladder is diverse, and, at times, different entities with distinct prognostic and managerial implications may have significant morphologic overlap. The presence of a neoplasm with an unusual morphologic appearance, such as an undifferentiated spindled, or plasmacytoid pattern may necessitate immunohistochemistry to establish the diagnosis. In this review, we discuss a series of distinct diagnostic scenarios, including high-grade undifferentiated carcinoma versus prostatic adenocarcinoma, enteric-type adenocarcinoma versus secondary colorectal adenocarcinoma, spindle cell proliferations, neoplasms with plasmacytoid morphology, endophytic tumors with a nested growth pattern, and flat urothelial lesions with atypia. We also discuss markers supporting urothelial differentiation in the context of a metastatic carcinoma from an unknown primary. The importance of using a morphologically derived differential diagnosis to guide the selection and interpretation of immunohistochemical studies is emphasized, and the varying utility (specificity) of the individual immunohistochemical markers within each setting is addressed.     

Pigmented spindle cell carcinoid tumour of the thymus with ectopic adrenocorticotropic hormone secretion: report of a rare variant and differential diagnosis of mediastinal spindle cell neoplasms

AIMS: A variety of histological variants of thymic carcinoid tumour have been described. A rare case of pigmented spindle cell carcinoid tumour of the thymus is documented and compared with the reported cases of thymic pigmented carcinoid tumour in the literature, with a discussion of the differential diagnosis of spindle cell tumours of the mediastinum. METHODS AND RESULTS: A thymic tumour with ectopic adrenocorticotropic hormone (ACTH) secretion was resected from a 24-year-old man suffering from Cushing's syndrome. Histological, immunohistochemical, and ultrastructural studies revealed an ACTH-producing spindle cell carcinoid tumour harbouring pigmented melanocytes. Among four thymic pigmented carcinoid tumours reported before, only one was similar to the present case by being also an ACTH-secreting pigmented spindle cell thymic carcinoid tumour. The clinicopathological features of this tumour distinguish it from a spindle cell thymoma, spindle cell thymic carcinoma, and other mediastinal spindle cell tumours. CONCLUSIONS: This case illustrates an extremely rare variant of thymic carcinoid tumour exhibiting a spindle cell morphology and harbouring pigmented melanocytes. Awareness of this histological variant is important in the differential diagnosis of spindle cell tumours of the mediastinum.     

Glandular lesions of the urinary bladder:clinical significance and differential diagnosis

Williamson S R, Lopez‐Beltran A, Montironi R & Cheng L
(2011) Histopathology  58 , 811–834
Glandular lesions of the urinary bladder: clinical significance and differential diagnosis A variety of glandular or pseudoglandular lesions may be seen in the urinary bladder, ranging from those that are entirely benign to aggressive‐behaving malignant primary and secondary tumours. Lesions with minimal to no evident premalignant potential include several proliferative and reactive processes, such as cystitis cystica and cystitis glandularis, although the possibility exists for confusion of such lesions with an infiltrative neoplasm, particularly in limited biopsy specimens. Similarly, ectopic tissues of Müllerian origin may be seen occasionally in the urinary bladder and their differentiation from a true glandular neoplasm is important to avoid improper treatment. As urothelial carcinoma has a propensity for divergent differentiation, a wide spectrum of morphological variants exists with varying degrees of glandular differentiation. Some such variants have demonstrated clinical behaviour that is more aggressive than their histology would suggest, thus deserving recognition and potentially different treatment. In this paper, we review the glandular lesions of the urinary bladder ranging from benign proliferative processes to malignant primary and secondary neoplasms, with emphasis on clinical significance and features useful in resolving their differential diagnoses.     

Histiocytic sarcoma: diagnosis and differential diagnosis

Two cases of clinical diagnosis of tumour of the trachea and tumour of the stomach are described in a 42- and 52-year-old males. Immunohistochemical and ultrastructural methods were used to prove the histiocytic nature of the tumour cells which were morphologically similar to poorly differentiated carcinoma and large cell lymphosarcoma.     

SYT在诊断单相纤维型滑膜肉瘤中的价值

目的 探讨SYT在单相纤维型滑膜肉瘤(monophasic fibrous synovial sarcoma,MFSS)的诊断及与其它梭形细胞肿瘤鉴别诊断中的作用.方法 收集MFSS 36例、其它梭形细胞肿瘤32例,其中包括恶性外周神经鞘膜瘤7例、纤维肉瘤6例、平滑肌肉瘤4例、恶性纤维组织细胞瘤7例和孤立性纤维性肿瘤8例,检测sYT蛋白在上述病例中的表达.结果 SYT在MFSS中的阳性表达率为91.67%(33/36),其中15例呈弥漫强阳性表达(>80%的瘤细胞核呈强阳性),12例呈不同程度的阳性表达,50%～80%的瘤细胞核呈强阳性表达.SYT在其他梭形细胞间叶肿瘤中的阳性表达率为59.37%(19/32),其中6例呈弥漫强阳性表达(>80%的瘤细胞核呈强阳性),7例呈不同程度的阳性表达,50%～80%的瘤细胞核呈强阳性.结论 SYT蛋白在MFSS和其他梭形细胞肿瘤中均有较强的阳性表达,提示SYT抗体在MFSS与其他梭形细胞肿瘤的鉴别诊断中作用有限.     

Chromosomal abnormalities in inflammatory pseudotumor of the urinary bladder

Inflammatory pseudotumors of the urinary bladder are rare, benign, nonepithelial tumors. Fewer than 30 have been reported, and no data are available on their karyotypic characteristics and/or the molecular mechanisms of pathogenesis. We performed short-term culturing and cytogenetic analysis of an inflammatory pseudotumor of the bladder, finding a der(20)t(12;20)(q13 approximately q15;q13) as the only cytogenetic aberration. The detection of a 12q13 approximately q15 rearrangement in the inflammatory pseudotumor indicates that this lesion is pathogenetically related to other benign mesenchymal tumors displaying, for example, lipogenic or leiomyomatous differentiation, something that is in sharp contrast to the karyotypic profile of epithelial tumors of the urinary bladder mucosa.     

An approach to the classification of spindle cell proliferations in the urinary bladder

Spindle cell proliferations of the urinary bladder are uncommon but may cause significant diagnostic difficulty resulting from the degree of morphologic overlap between clinically benign and malignant lesions. These difficulties may be amplified in small biopsies because some of the more specific diagnostic features may not be present for evaluation. In addition, the number of different diagnostic terms applied to the same entity has added confusion to this diagnostic area. This review discusses the nomenclature, morphologic criteria, and immunohistochemical features used to classify spindle cell proliferations occurring in the urinary bladder, including those with myofibroblastic, smooth muscle, skeletal muscle, epithelial (sarcomatoid urothelial carcinoma), fibroblastic, and neural differentiation. A separate discussion of 5 challenging differential diagnostic scenarios is also presented.     

Immunohistochemistry in the differential diagnosis between primary and secondary intestinal adenocarcinoma of the urinary bladder.

Distinguishing between primary adenocarcinomas and secondary colonic adenocarcinomas of the urinary bladder is often difficult because they appear morphologically similar but invariably require different treatment strategies. The aim of the study was to define the utility of a limited immunohistochemical panel consisting of CDX-2, cytokeratins 7 (CK7) and 20 (CK20), and carcinoembryonic antigen (CEA) in differentiating primary from secondary bladder adenocarcinomas. Formalin-fixed, paraffin-embedded tissues from 8 primary bladder adenocarcinomas and 23 colorectal adenocarcinomas involving the bladder were included in the study. Statistical analysis was performed using the Fisher exact test. The majority (87.5%) of primary bladder adenocarcinomas were CDX-2 negative, and only one case of primary bladder adenocarcinoma was positive, while CDX-2 was strongly expressed in the nucleus of all cases of secondary (colonic) bladder tumor (P < 0.0005). Five cases (62.5%) of primary bladder adenocarcinoma and one case (4.3%) of secondary bladder tumor showed positive staining for CK7 (P = 0.002), whereas CK20 showed positive staining in five cases (62.5%) of primary bladder adenocarcinoma and in all the secondary bladder tumors (P = 0.012). All 23 secondary bladder tumors and 7 primary bladder adenocarcinomas (87.5%) expressed CEA (P = 0.25). These data demonstrate that a restricted immunohistochemical panel consisting of CDX-2, CK7, CK20, and CEA may be of use in differentiating primary bladder adenocarcinoma from secondary adenocarcinoma of colorectal origin.     

Soft tissue clear cell sarcoma. Morphology, differential diagnosis and tumor classification

Clear cell sarcomas of tendons and aponeuroses were first described by Enzinger in 1965 and are characterized by the occurrence in young adults, frequent location in the distal lower extremity and slow, but often relentless clinical course. The histologic features of 5 own cases are presented, the cellular arrangement in nest-, cluster- or "ball"-like formations and a prominent nucleolus are emphasized as most reliable diagnostic patterns. Some aspects of differential diagnosis are discussed, especially those concerning its histologic distinction from fibrosarcomas, malignant melanomas, malignant Schwannomas and synovial sarcomas. The electron microscopic examination of one case revealed findings which may be considered as typical for tumors developed from neural crest derived cells: envelopment of many tumor cells by basal lamina-like structures, specialized cellular contacts, interdigitations of cellular processes and "wrapping around"-phenomena (so-called mesocollagen formation). Some neurosecretory granules (not described till now in clear cell sarcomas) and fibrous long spacing collagen further support the suggestion that clear cell sarcomas pertain to the group of tumors with relationship to neuroectodermal cells and tissues. We feel that, because of their typical histologic picture and their particular clinical behavior, they should not be regarded as malignant (soft tissue) melanomas or malignant (melanotic) Schwannomas but retained as a defined clinico-pathological entity.     

膀胱炎性假瘤—假肉瘤性肌纤维母细胞增生

目的：探讨膀胱炎性假瘤的病理学特征。方法：描述4例膀胱炎性假瘤的临床病理及免疫组化特征并复习有关文献。结果：男女各2例患者,年龄分别为36,27,36,8岁,肿瘤直径分别为3,4,3及5cm,主要临床症状为肉眼血尿或排尿困难,组织学检查：肿瘤主要成分为梭形细胞,胞质嗜酸性,有大的卵圆形至梭形泡状核,有1－2个明显的核仁,分裂象少见,无不典型核分裂,3例免疫表型,3例Vim呈弥漫阳性;α-SMA（2例）及MSA（1例）局部少数细胞阳性;2例AE1／AE3多数细胞呈阳性,Des,Myo及EMA均阴性。3例术后分别随访40,16,14个月无复发,1例为近期病例,结论：病损为一种良性,非肿瘤性肌纤维母细胞增殖,要避免误诊为恶性。     

CT在甲状腺肿瘤鉴别诊断中的应用价值

目的探讨CT在甲状腺良恶性肿瘤诊断及鉴别诊断中的价值。方法经手术后组织病理学证实的39例良恶性甲状腺肿瘤患者,其中男性17例,女性22例,年龄33～78岁,平均年龄45．6岁。行颈部CT平扫8例．增强扫描31例。分析其良恶性甲状腺肿瘤的CT表现,并进行统计学处理。结果7例甲状腺腺瘤平扫时边界清晰．内部主体低密度且密度均匀;3例可见到完整或不完整的囊壁。4例结节性甲状腺肿局限型,低密度影。25例恶性甲状腺肿瘤平扫时成等密度或混杂密度,边界不清,增强扫描强化不均,并向邻近组织侵犯。结论有无对周围组织的浸润、包膜是否完整、边界是否清晰、轮廓是否规则、密度均匀与否及颈部淋巴结有无肿大等特点,对鉴别甲状腺肿瘤良恶性有很大作用。CT在甲状腺肿瘤的诊断和鉴别诊断中具有重要作用。     

Ovarian spindle cell lesions: a review with emphasis on recent developments and differential diagnosis

Ovarian lesions composed of spindle cells comprise a heterogeneous group; most are neoplastic but several non-neoplastic conditions are also composed of spindle cells. This review discusses the main differential diagnoses of an ovarian spindle cell lesion, especially concentrating on the recent literature. The majority of ovarian spindle cell lesions fall into the broad category of fibromatous neoplasms whereas others in the sex cord-stromal group may also be composed of spindle cells, including thecomas, granulosa, and Sertoli-Leydig cell tumors and rarer neoplasms, such as sclerosing stromal tumor and signet-ring stromal tumor. In the recent past there have been several major contributions on various aspects of ovarian spindle cell lesions, including cellular and mitotically active cellular fibromatous lesions, smooth muscle neoplasms, and metastatic gastrointestinal stromal tumors. Other mesenchymal or epithelial tumors and mixed epithelial and mesenchymal neoplasms may also enter into the differential diagnosis of an ovarian spindle cell lesion. Several non-neoplastic lesions may be composed of spindle cells, including massive edema, ovarian fibromatosis, stromal hyperplasia, and stromal hyperthecosis. Morphology remains the mainstay in diagnosis but immunohistochemistry may be invaluable in certain circumstances, one example being the identification of a metastatic gastrointestinal stromal tumor within the ovary.     

Anti-mesothelial markers in sarcomatoid mesothelioma and other spindle cell neoplasms

AIMS: To undertake a comparative evaluation of three antimesothelial markers (thrombomodulin, cytokeratin 5/6 and calretinin) with broad spectrum cytokeratin (AE1/AE3) in differentiating between sarcomatoid mesothelioma and a spectrum of spindle cell neoplasms. METHODS AND RESULTS: Thirty-one malignant sarcomatoid mesotheliomas were studied. Calretinin expression was focally identified in 12 (39%) tumours and thrombomodulin and cytokeratin 5/6 immunoreactivity was seen in nine (29%) cases. In comparison there was strong diffuse cytoplasmic reactivity with the broad spectrum cytokeratin (AE1/AE3) in 24 of 31 (77%) tumours. Thirty mixed spindle cells neoplasms were studied. No calretinin expression was identified in any case. Thrombomodulin immunoreactivity was identified in four (16%) cases (two angiosarcomas, two high-grade sarcomas, not otherwise specified). Cytokeratin 5/6 expression was seen in one high-grade pulmonary sarcoma originally termed malignant fibrous histiocytoma. None of the antimesothelial markers was expressed in the four spindle cell carcinomas studied. In contrast, broad spectrum cytokeratin was diffusely expressed in all four spindle cell carcinomas (three pulmonary, one renal), both synovial sarcomas, both malignant mixed Müllerian tumours, one of three pulmonary leiomyosarcomas and two of nine sarcomas, not otherwise specified. CONCLUSIONS: Immunohistochemistry has a more limited role in the diagnosis and distinction of sarcomatoid mesothelioma from other spindle cell neoplasms. The combination of a broad spectrum cytokeratin with calretinin combines both high sensitivity (77% for AE1/AE3) with high specificity (100% for calretinin) for sarcomatoid mesothelioma and can be diagnostically useful. The mesothelial markers, thrombomodulin and cytokeratin 5/6, are not useful alone in the diagnosis of sarcomatoid mesothelioma as each shows insufficient antibody sensitivity, although together they complement calretinin.     

Fine-needle aspiration cytology of spindle cell neoplasms of the adrenal gland.

Three spindle cell neoplasms were encountered in a series of 46 FNA of the adrenal performed between 1984 and 1991. These neoplasms included a recurrent undifferentiated adrenal cortical carcinoma (ACC) with a predominant spindle cell pattern, a pheochromocytoma (PC), and a metastatic desmoplastic malignant melanoma (DMM). Cytologically, the ACC was characterized by the presence of numerous microtissue fragments composed of spindle-shaped malignant cells with oval to spindle-shaped nuclei, one or more nucleoli, and bipolar cytoplasmic processes. In some areas the tumor cells were dissected by vascular channels. The background contained abundant metachromatic stroma as well as individually scattered tumor cells. The PC was composed predominantly of loosely cohesive spindle-shaped cells along with more polygonal shaped cells with delicate faintly staining granular cytoplasm. The tumor cells exhibited mild anisonucleosis. The tumor fragments were well vascularized by arborizing delicate capillary channels. The DMM was composed of microtissue fragments, interlacing fascicles and loose aggregates of spindle-shaped malignant cells with hyperchromatic nuclei, small nucleoli, and an absence of cytoplasmic pigment. In each case ancillary studies including immunocytochemistry and electron microscopy (EM) were helpful in the differential diagnosis. The ACC was negative for cytokeratins, neuron-specific enolase (NSE), and muscle-specific actin (HHF), but displayed strong positivity for vimentin as well as characteristic whorls of smooth endoplasmic reticulum by EM. The PC was positive for NSE and chromogranin with no EM performed. The DMM stained for S-100 and vimentin but was negative for HMB-45, cytokeratin, and HHF. EM examination revealed rare atypical premelanosomes.(ABSTRACT TRUNCATED AT 250 WORDS)