[922] Nodular Periorchitis: A Morphological and Immunohistochemical Study of 13 Cases

H Miyamoto, E Montgomery, JI Epstein. The Johns Hopkins Hospital, Baltimore

Background: Nodular periorchitis is a rare intrascrotal mass that has been thought to represent a reactive process arising mostly in the tunica vaginalis and less commonly in the epididymis, spermatic cord, or tunica albuginea. Numerous synonyms have been proposed for this entity. These include "fibrous pseudotumor", "nodular and diffuse fibrous proliferation", "chronic proliferative periorchitis", and "inflammatory pseudotumor", among others. Its histology has been mainly described in case reports and there are no series on its immunohistochemical features.
Design: A database search (2000-2008) from the consult files of one of the authors, as well as archival files of Surgical Pathology at our institution, identified 13 cases in which paraffin blocks or unstained slides were available for further studies. CD34 and calretinin/cytokeratin results were recorded for the lesional spindle cells not blood vessels and mesothelium, respectively.
Results: Patients' ages ranged from 19 to 75 years old (mean 41.9 years). All men presented with scrotal mass, with 6 (46%) cases also having a clinical history of hydrocele. Six men were treated by orchiectomy, while the remaining 7 men underwent excisional biopsy. Histologically, the lesions could be subdivided into 3 types: 1) “plaque-like”, consisting of dense fibrous tissue with clefts without significant inflammation identical to a pleural plaque (5 cases); 2) “inflammatory sclerotic” with dense fibrous tissue containing lymphocytes (diffusely or aggregates or germinal centers), plasma cells, and an increased capillary network (6 cases); and 3) “myofibroblastic” (2 cases) consisting of reactive appearing tissue-culture-like cells with numerous capillaries and sparse chronic inflammation. All cases were negative for beta-catenin and ALK-1. Ki-67 showed <1% positivity in all but 2 cases, which had 5% positivity. Results for other stains are listed in table.

ActinDesminCytokeratinCalretininCD34
Plaque-like4/52/5 (1 focal)2/5 (2 focal)1/5 (1 focal)2/5 (1 focal)
Inflammatory/Sclerotic5/6 (4 focal)0/63/6 (1 focal)3/6 (3 focal)5/6 (2 focal)
Myofibroblastic2/22/2 (1 focal)2/22/2 (1 focal)0/2



Conclusions: There are 3 distinct histologic patterns seen in nodular periorchitis, although their immunohistochemical profile has overlapping features. Because of negative stains for ALK-1 and beta-catenin, nodular periorchitis appears distinct from inflammatory myofibroblastic tumor and fibromatosis, respectively, seen in other organs.
Category: Genitourinary (including renal tumors)

Monday, March 22, 2010 1:00 PM

Poster Session II # 95, Monday Afternoon

 

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