Primary Retroperitoneal Müllerian Adenocarcinoma: A Case Report and Literature Review
A 54-year-old primiparous woman presented with a 6-month history of mild abdominal pain and distension of the right portion of the abdomen. Her family history was not contributory. Her past surgical history included a total thyroidectomy for papillary carcinoma followed by radioiodine therapy 3 years before.\nPhysical examination revealed a slightly tender, ill-defined mass over the left abdomen. The remaining systemic examination did not reveal any coexistent lesion. Laboratory tests, including complete blood count, chemistry profile, urinalysis and chest X-ray, were all within normal limits. Serum tumor markers were negative.\nAn abdominal ultrasound (US) documented the presence of a coarse, partially cystic mass in the right retroperitoneal region. Abdominopelvic CT and MRI revealed a large unilocular cystic mass measuring 11 cm with an enhancing solid portion and partial water content, located in the retroperitoneal space adjacent to the lower pole of the right kidney, with wall calcifications (fig. ). There was no evidence of extracystic extension or distant metastasis. On suspicion of a hydatid cyst, serological tests were performed and yielded negative results. A gynecological examination, including hysteroscopy and Pap smear, was also performed. It was negative for utero-adnexal pathology.\nThe patient underwent laparotomy with subcostal transverse incision. On opening the peritoneal cavity, ascitic fluid was found and sampled. Cytological examination of the fluid did not reveal the presence of malignant cells. Abdominal cavity exploration revealed no abnormal findings in the liver, stomach, large bowel and spleen, and the uterus, ovaries, fallopian tubes and appendix were all normal. Sequential exploration of the small intestine revealed the presence of an exophytic lesion about 1 cm in diameter, which was removed and whose definitive histological examination was compatible with fibroma of the small intestine. A large, encapsulated cystic mass was found in the right retroperitoneum, below the lower pole of the right kidney that was displaced posteriorly and cranially to the mass. The cecum, right colon and right colic flexure were displaced medially to the mass. The mass was dissected from the surrounding structures. A fragment of the cystic wall was sent for extemporaneous histological examination and it was compatible with a fibrous wall denuded of lining epithelium. Complete excision of the cyst was performed. The postoperative period was uneventful, and the patient was discharged home 5 days after surgery.\nThe gross pathological findings showed a 12 × 10-cm cystic mass with a smooth surface. The cystic wall measured 0.3 cm at maximum thickness. The tumor was composed of malignant epithelial and stromal components. Microscopically, the fibrous wall of the cyst delimited an extensively necrotic lesion containing chronic inflammation, calcification, cholesterol crystals and hemorrhagic extravasation. On hematoxylin and eosin staining, the entire tumor showed cellular whorls dispersed amidst pale sarcomatous stroma. The cells in whorls were round to short, spindle shaped and had moderate mitotic activity. The sections, however, revealed whorled glandular areas.\nA panel of immunohistochemical tests was performed: whorled glandular areas were positive for cytokeratin (CK19) and negative for vimentin, confirming their epithelial nature; they were also negative for CK20 and calretinin. The stromal component of the tumor, highlighted on vimentin stain (vimentin), was positive for CD10. No immunoreactivity to estrogen and progesterone receptors was found. The presence of necrosis, cytonuclear atypia and immunophenotypic features were compatible with PRMA (fig. ).\nSix courses of adjuvant chemotherapy were administered with carboplatin at a dose of 5 AUC and taxol 175 mg/mq/ev. A follow-up abdominal CT, performed 9 months later, was negative for tumor recurrence. Written informed consent was obtained from the patient for publication of this case report and all accompanying images.