IgG4-related disease diagnosed in a paratesticular pseudotumor simulating malignancy, in a patient with retroperitoneal fibrosis.

IgG4 related disease is a term used to describe a fibroinflammatory condition characterized by storiform fibrosis, inflammation with a dense lymphoplasmocytic infiltrate rich in plasma cells expressing IgG4, and often, if not always, raised serum levels of IgG4. We report a case of a patient with a past history of retroperitoneal fibrosis presenting with a swollen left testicle, who underwent an orchidectomy due to suspicion of malignancy. The surgical specimen revealed a paratesticular pseudotumor with histopathological and immunohistochemical characteristics of IgG4 related disease. To the best of our knowledge, just nine such cases have previously been reported, of which only three were manifestations of systemic disease, as in the present case. Whilst it is important to recognize the clinical and radiological features of this entity, histopathology is often essential in order to confirm the diagnosis.

Deciduosis peritoneal difusa simulando un mesotelioma deciduoide en una paciente primigrávida / Diffuse peritoneal deciduosis mimicking deciduoid mesothelioma in a primigravida patient

Paciente de 36 años, primigesta, con gestación de 37 semanas y sin antecedentes de interés, a la que se le practica una cesárea por fracaso de inducción. Tras realizar la laparotomía, se objetivan múltiples nódulos firmes y blanquecinos, de manera diseminada por toda la cavidad abdominal, de tamaños comprendidos entre 0,2-0,5cm. Con sospecha clínica de carcinomatosis peritoneal, se realizan biopsias de ovario, vejiga, epiplón y apéndice epiploico. Tras la intervención, se realiza TAC toraco-abdomino-pélvico, que es informado como hallazgos en relación con carcinomatosis y ascitis. El estudio morfológico e inmunohistoquímico apoyó el diagnóstico de deciduosis peritoneal difusa. Presentamos un caso poco frecuente y muy exhuberante de deciduosis peritoneal. Cuando es difusa, es importante realizar el diagnóstico diferencial, principalmente con metástasis tumorales y el mesotelioma deciduoide, ya que a diferencia de estas entidades, la deciduosis peritoneal difusa es un proceso que suele evolucionar a la regresión espontánea tras el parto (AU)

We report a case of rare, florid peritoneal deciduosis in a 36 year old patient who underwent a caesarean section at the 37th week of her first pregnancy after labour induction failed. She had an unremarkable previous medical history. On laparotomy, multiple firm, whitish nodules measuring between 0.2 and 0.5cm were seen in the abdominal cavity. As peritoneal carcinomatosis was suspected, biopsies were taken of ovaries, bladder, omentum and appendix. A thoraco-abdominopelvic CT scan was performed postoperatively which showed abdominal-peritoneal involvement and ascites. Histopathology and immunohistochemistry confirmed a diagnosis of diffuse peritoneal deciduosis. Diffuse peritoneal deciduosis must be carefully differentiated from tumour metastases and deciduoid mesothelioma as it usually regresses spontaneously after delivery (AU)