Umbilical metastasis as an initial presentation of gastrointestinal stromal tumour diagnosed on aspiration cytology.

Umbilical metastasis is a rare event, with a majority being adenocarcinomas. Metastatic squamous cell carcinoma, small cell carcinoma, lymphoma, melanoma, and rarely malignant mesenchymal tumours like leiomyosarcoma can occur as umbilical nodules. These often emerge during a known malignancy, but once in a while they may be an initial presentation of an undetected tumour. An extensive literature search failed to reveal a case of gastrointestinal stromal tumour (GIST) with umbilical metastasis as an initial presentation. We believe that this is an exceptional phenomenon. The diagnosis may easily be missed considering the rarity of this occurrence. A history of primary diagnosis of GIST, when available, is helpful. Here we present cytological findings of metastatic GIST presenting as an umbilical lump, where the diagnosis was reached with the help of limited immunocytochemistry. A timely diagnosis is valuable for locating the primary and initiating surgical management, which may have survival benefits for the patient.