IgG4-related para-testicular fibrous pseudotumor- A rare benign testicular mass mimicking malignancy: A case report and literature review

Abstract

Para-testicular fibrous pseudotumors (PFP) are rare benign reactive lesions comprising of 6 % of para-testicular masses. Often misdiagnosed as malignant due to clinical and radiological overlap, they are frequently treated with aggressive surgery. We report a case of a 70-year-old male with a left inguinal swelling diagnosed post-orchidectomy as PFP. Histopathology revealed collagen-rich fibrotic tissue with lymphoplasmacytic infiltrates and IgG4-positive plasma cells. While PFP treatment requires surgical resection, testicle-sparing procedures with intraoperative frozen section assessment may prevent unnecessary orchidectomy. Further studies are needed to establish diagnostic protocols and explore the association between PFP and IgG4-related diseases.

Highlights

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PFPs mimic malignancy and cannot be reliably differentiated using ultrasound or MRI.
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Studies suggest it to be among the spectrum of IgG-4 related disorders.
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Radical orchidectomy is often performed as a result of uncertain diagnosis.
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Frozen section assessment can help in avoiding unnecessary orchidectomies.

1 Introduction

Para-testicular fibrous pseudotumors (PFP) are rare, non-neoplastic benign reactive tumor-like lesions, accounting for only 6 % of all para-testicular masses. ^, The etiopathogenesis for their occurrence has not been determined although they might be associated with IgG4 pathology. ^, Despite it’s rarity, it is the second most common benign lesion of the para-testicular region. PFP is not listed in World health organization’s classification of tumors due to its benign nature. They are often aggressively treated as they mimic testicular neoplasms and cannot be differentiated from the latter through clinical and radiological investigations. It is difficult to establish the diagnosis in the pre-operative period, with diagnostic modalities like scrotal magnetic resonance imaging (MRI) having been scarcely explored due to the rarity of their occurrence. ^, We report a case of a 70-year-old man who presented with an inguinal swelling, later found to have a PFP through pathological examination of the orchidectomy specimen.

2 Case presentation

A 70-year-old male patient presented with a left inguinal swelling which developed insidiously 1 month ago and gradually progressed to the size at presentation. He had a history of an open right inguinal hernioplasty performed 20 years ago. On physical examination, penis and scrotum were normal in development. Cough impulse was present with a hard, non-tender left testis. An indirect complete inguinal omentocele was felt and confirmed by the deep ring occlusion test. No apparent abnormalities were palpable in the contralateral testis and scrotum. Retro-peritoneal and inguinal lymph nodes were not palpable. Scrotal ultrasound revealed a polycystic heterogeneous lesion with a left inguinal hernia containing bowel and omentum ( FIG-1 A, B, C). An open left inguinal hernioplasty was performed along with a left high orchidectomy, in suspicion of a malignant testicular mass. Surgery was performed under spinal anesthesia with the patient in supine position. An enlarged, grey-brown left testis with an intact capsule was removed successfully with attached cord structures and sent for histopathologic examination. On cut-section, a solid, firm greyish-white lesion measuring 4x3x2cm was noted with a focal cyst which exuded clear fluid ( FIG-2 ). The lesion was surrounded by normal testicular parenchyma in the periphery. Pathological examination revealed an ill-circumscribed lesion composed of hypocellular collagen-rich hyalinized fibrotic tissue with storiform features, interspersed with lymphoplasmacytic infiltrate. The epididymis showed a benign cyst lined by flattened cuboidal epithelium with areas of fibrosis in the adjacent cyst wall. Staining with Masson trichome confirmed the presence of collagenized stroma. Immunohistochemistry for IgG4 highlighted plasma cells ( Fig. 3 A, B, C). No evidence of nuclear atypia, mitosis, or necrosis was reported. Post-op period was uneventful. Follow-up after 6 months showed no recurrence, complications or need for further treatment.