IgG4-related disease of the paratestis in a patient with Wells syndrome: a case report

BACKGROUND: We report a case of a 33-year-old man who presented with immunoglobulin (Ig)G4-related disease (IgG4-RD) forming a pseudotumor in the left paratesticular region during oral administration of corticosteroid for Wells syndrome, which involves cellulitis with eosinophilia. CASE PRESENTATION: The patient was introduced to our institution from a private hospital with a 3-month history of asymptomatic left scrotal mass. A 5-cm diameter nodule was palpable in the left scrotum. Tumor lesion in the left paratestis involving the epididymis and spermatic cord was observed on computed tomography and magnetic resonance imaging. Blood testing showed no abnormalities other than a minimal increase in C-reactive protein levels. Urine examination likewise revealed no significant findings. Left radical orchidectomy was performed under a diagnosis of left paratesticular neoplasm suspected as malignant tumor. The tumor was pathologically identified as IgG4-RD of the left paratestis involving the epididymis and spermatic cord. CONCLUSIONS: We present a first description of IgG4-RD in a patient with Wells syndrome and the ninth case of IgG4-RD in a scrotal organ, and discuss this very rare entity with reference to the literature. VIRTUAL SLIDES: The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/13000_2014_225