Splenic Epstein-Barr Virus-Associated Inflammatory Pseudotumor.

Splenic inflammatory pseudotumor (IPT) is an uncommon lesion with an inflammatory morphologic aspect that often poses a diagnostic challenge. The etiology of IPT can be infectious, autoimmune, reactive, or neoplastic. Splenic Epstein-Barr virus (EBV)-associated IPTs form a subset of splenic IPTs in which there is a spindle cell component infected by EBV. The best characterized and most frequent subgroup of splenic EBV-associated IPT is IPT-like follicular dendritic cell tumor. This review also focusses on EBV-associated splenic IPTs without follicular dendritic cell marker expression. These lesions are less well characterized, making the differential diagnosis with other splenic lesions even more difficult. Recently, increased numbers of immunoglobulin G4-positive plasma cells and the presence of numerous granulomas have been reported in EBV-associated IPTs, and this can add to the difficulties in recognizing the neoplastic nature of these lesions. Herein, we also review the epidemiology, clinical features, histologic morphology, immunohistochemistry, electron microscopy, and pathogenesis of EBV-associated IPTs.

Detection of Epstein-Barr virus in inflammatory pseudotumour of the spleen: a case report.

BACKGROUND: Various types of benign and malignant splenic tumours including hemangiomas, lymphagiomas, hamartomas, hemangiosarcomas, malignant lymphomas and metastatic carcinomas share radiological characteristics making it impossible for a physician to determine the definite aetiology of splenic masses noninvasively without histopathological evaluation. It is important that physicians recognize the importance of a careful and continuous follow-up since inflammatory pseudotumours (IPT) are considered to be tumours with an intermediate malignant potential based on their behaviour when they arise in other locations. METHODS: Our patient, a 60-year-old woman was evaluated using laboratory, gastroscopy, computed tomography and surgical methods. The resected tumour was evaluated using immunohistochemical methods. RESULTS: The patient presented with weight loss, nausea and vomiting, symptoms lasting over a course of a few months. The splenic mass was found incidentally at the time of work up for gastritis and cholelithiasis. Histologically, the tumour differed from typical splenic architecture being composed of atypical spindle cells with inflammatory elements; numerous plasma cells, macrophages, eosinophils and lymphocytes. CONCLUSIONS: Although very difficult to diagnose at initial presentation, it is very important for the physician to be aware of the importance of a careful diagnosis since IPT of the spleen are rare and considered to be tumours with an intermediate malignant potential.

Multimodality imaging of Epstein-Barr virus-associated inflammatory pseudotumor-like follicular dendritic cell tumor of the spleen: case report and literature review.

Inflammatory pseudotumors (IPTs) are rare tumors of unknown etiology; however, there is a strong association with the Epstein-Barr virus (EBV). EBV-positive IPTs are typically found in the liver and spleen. While many EBV-positive splenic IPTs contain follicular dendritic cell (FDC) proliferations, they are not aggressive such as with conventional FDC tumors. EBV-positive splenic IPTs have been reported with low malignant potential. We present a case with multimodality imaging of an EBV-positive IPT-like tumor with FDC features.

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.

Inflammatory pseudotumor-like follicular dendritic cell tumor of liver and spleen: granulomatous and eosinophil-rich variants mimicking inflammatory or infective lesions.

Inflammatory pseudotumor-like follicular dendritic cell (FDC) tumor is an uncommon, Epstein-Barr virus-associated neoplasm of the liver or spleen, characterized by spindly tumor cells dispersed in a background of small lymphocytes and plasma cells. We report 6 diagnostically challenging cases in which the neoplastic component is further overshadowed by granulomas or eosinophils. The patients included 2 men and 4 women with a median age of 45.5 years, and 1 of them showed concurrent involvement of the liver and spleen. The presence of extensive coalescent epithelioid granulomas in 3 splenic tumors and 3 liver tumors raised the possibilities of an infective process or sarcoidosis. In another liver tumor, the massive infiltrate of eosinophils, accompanied by geographic eosinophilic abscesses, suggested parasitic infestation or so-called eosinophilic granuloma of the liver. However, scrutiny of the tissue between the granulomas or among the eosinophils revealed scattered atypical spindly cells with indistinct cell borders, large vesicular nuclei, and distinct nucleoli. The atypical cells were positive for FDC markers on immunostaining (CD21, CD35) and Epstein-Barr virus on in situ hybridization. Thus, a diagnosis of inflammatory pseudotumor-like FDC tumor could be confirmed. Awareness of the granulomatous and eosinophil-rich variants of this tumor type will facilitate the correct diagnosis to be made.

Epstein-Barr virus-positive inflammatory pseudotumour and inflammatory pseudotumour-like follicular dendritic cell tumour.

Various splenic inflammatory pseudotumours are reported to be infected with Epstein-Barr virus (EBV), which is thought to be associated with the pathogenesis of the lesion. The term "inflammatory pseudotumour (IPT)-like follicular dendritic cell tumour", all cases of which are also EBV positive, has recently been proposed. Here, we describe the imaging findings of these splenic tumours and present the cases of an IPT-like follicular dendritic cell tumour and two EBV-positive inflammatory pseudotumours in two female patients and one male patient. These splenic lesions were found incidentally on pre-operative or post-operative screening or at medical check-up. CT performed on all three patients revealed low-density solitary masses in the spleen. MRI was performed on one patient; the solitary mass demonstrated isointensity on T(1) weighted images and low intensity on T(2) weighted images relative to the surrounding splenic parenchyma. Dynamic MRI study revealed that the mass did not enhance on the early phase but enhanced to the same degree as the surrounding splenic parenchyma on the delayed phase. The imaging findings are almost identical to those found in conventional IPT because the morphology is similar in both cases; however, attention should be paid to this new entity in the diagnosis of splenic lesions because of its neoplastic nature. Longer follow-up is also necessary for these patients compared with those with conventional IPT.

Granulomatous inflammatory pseudotumor of the spleen: association with Epstein-Barr virus.

A 74-year-old woman with a clinical history of invasive ductal carcinoma of the breast was found to have a splenic mass during a routine radiographic survey. Splenectomy revealed a 3-cm well-demarcated lesion, which on histopathologic examination consisted of heterogeneous inflammatory cells. A striking feature of the lesion was the presence of innumerable well-formed non-necrotizing granulomas. Immunohistochemical studies confirmed the lesion to be composed mainly of mixed T and B lymphocytes, histiocytes, and plasma cells. No spindle cell component was evident on light microscopic examination or by immunohistochemical staining for smooth muscle actin, anaplastic lymphoma kinase, or follicular dendritic cell markers CD21 and CD35. Interestingly, Epstein-Barr virus-encoded RNA and latent membrane protein were detected by in situ hybridization and immunohistochemistry in numerous lymphohistiocytic cells within the lesion, but not in surrounding uninvolved splenic tissue. To our knowledge, this case represents a rare example of splenic inflammatory pseudotumor with exuberant granulomatous reaction in association with Epstein-Barr viral infection.

A case of an intraventricular inflammatory pseudotumor presumably caused by Epstein-Barr virus infection.

BACKGROUND: Inflammatory pseudotumor primarily affecting the CNS is an extremely rare lesion with uncertain etiology in most cases. CASE DESCRIPTION: A 67-year-old man developed involuntary movement disorder of the left upper extremity. On MRI, a solid homogeneously-enhanced tumor was noted in the right lateral ventricle adjacent to the thalamus. He had histories of right thalamic hypertensive hemorrhage and recurrent chronic nasal sinusitis associated with an orbital mass lesion, presumably an IP. Partial removal of the tumor yielded a diagnosis of IP associated with EBV infection. CONCLUSION: The simultaneous occurrence of multiple IPs was presumably because of an exaggerated immune process after EBV infection. Inflammatory pseudotumor should be considered in any case of intraventricular mass lesion.