Dysphagia, melanosis, gastrointestinal stromal tumors and a germinal mutation of the KIT gene in an Argentine family.

Gastrointestinal stromal tumors (GIST) are the most common mesenchymatous neoplasms of the human digestive tract. They locate preferentially in stomach, duodenum or small bowel. Usually sporadic, familial cases unrelated to neurofibromatosis may be due to germline mutations in KIT or PDGFRA. We describe the first Argentine family with GIST in which we found, diffuse cutaneous melanosis, lentiginosis, and dysphagia. Dysphagia was not observed in the four families previously described with the same mutation. Histopathology resulted consistent with GIST, and tumor immunohistochemistry was likewise positive for DOG-1, CD117 (KIT) and CD34. The search for germline mutations identified the KIT c.1697T > C (p.559V > A) substitution in exon 11. Treatment with imatinib is furnishing positive results.