Castleman's disease mimicked melanoma metastasis in the mesentery - A case report

Castleman's disease (CD) is a rare and mainly asymptomatic cause of lymph node swelling. Often it is unicentric and located in the mediastinum. Due to rarity of the disease as well as a lack of symptoms, diagnosis proves to be challenging, especially when CD affects another region.

A 51-year old male underwent resection of a malignant melanoma. Further staging revealed an unclear abdominal mass located in the mesentery with close contact to small intestine. Under the assumption of metastasis, complete tumor removal including intestine resection and anastomosis was performed. Both, operation and postoperative phase proved uncomplicated. Surprisingly, however, histology revealed a benign lymphoproliferative disorder, CD.

There are several differential diagnoses for abdominal soft tissue tumor, such as: gastrointestinal stromal tumor, sarcoma, lymphoma, or metastasis. In reference to the resected melanoma described above, metastasis was assumed with subsequent oncological resection. Both, the reliable detection of CD as well as the exclusion of malignant disease (e.g. lymphoma) can only be achieved through pathology, in that specific tests fail yet to exist. The etiology of CD remains barely understood and based upon few cases reported complete surgical resection is recommended. However, the common form is meant to be benign.

The potential diagnosis of CD should be made more common to surgeons, especially in completely asymptomatic patients and non-superficial lesions, whereby close follow-up examination might be offered to patients.