Giant adenocarcinoma of unknown origin penetrating from the pelvic cavity to subcutaneous tissue: A case report and review of the literature

Abstract

Abstract. In this study, we present a case of a 43-year-old female patient who was admitted to our hospital due to a giant mass on the left buttock. Imaging tests revealed that the mass was a solid-cystic tumor with a large size of 143x430x180 mm, penetrating from the pelvic cavity to the subcutaneous tissue. Pathology tests indicated a metastatic mucinous adenocarcinoma which was most likely of gastrointestinal origin. However, there was no evidence to confirm the existence of malignant changes in the gastrointestinal tract. IntroductionIn clinical practice, patients who present with metastases but without a known primary cancer are often encountered. It is essential to determine the primary tumor and to treat it accordingly (1). However, occasionally it is difficult to identify the primary tumor site. Therefore, it is only possible to resect or treat the metastases. We report a case of a 43-yearold female patient with a giant origin-unidentified mucinous adenocarcinoma, measuring 143x430x180 mm, penetrating from the pelvic cavity to the subcutaneous tissue. The study was approved by the ethics committee of Wuhan General Hospital of Guangzhou Command, and consent was obtained from the patient involved. Case reportA 43-year-old female patient was referred to our hospital with a giant mass on the left buttock (Fig. 1). The mass was of negligible size when the patient first noticed it (approximately five years ago) and the mass gradually grew to the size of a quail's egg, without evident symptoms, including pain or limited activity. In November 2008, a percutaneous needle biopsy revealed metastatic mucinous adenocarcinoma. Pelvic CT and MRI scans demonstrated two solid-cystic lesions at the bottom of the pelvis, which were further confirmed by pelvic ultrasound to be a complex mass in the left adnexa and a right ovarian cyst. The patient underwent a left ovariectomy and right oophorocystectomy in another hospital, but the mass on the left buttock was not treated. No malignant changes were identified upon histological examination of any of the resected specimens. Following examination, the mass continued to increase in size and limited the patient's quality of life, with symptoms of local discomfort due to pressure stimuli.In November 2010, a contrast-enhanced CT scan revealed a giant solid-cystic mass with a size of 143x430x180 mm, penetrating from the pelvic cavity to the subcutaneous tissue of the left buttock, in which part of the mass was enhanced by contrast medium ( Fig. 2A and B). CT angiography revealed that the mass was fed by the tertiary branches of the left internal iliac artery (Fig. 2C and D). No adjacent bone destruction or lymph node metastasis was identified. Clinical examination revealed a large mass measuring 150x180 mm in the left buttock that was soft, painless, fluctuant, without skin redness, pigmentation or increased temperature.In mid-November 2010, surgery was performed to remove the mass (Fig. 3A). Intraoperative examination revealed that the mass was solid-cystic, with a capsule adherin...