Small cell carcinoma and primary malignant melanoma are rare esophageal malignancies with a poor prognosis and a typically delayed diagnosis.
Small Cell Carcinoma of the Esophagus
Small cell carcinoma of the esophagus is a very rare form of esophageal cancer: about 0.8 to 3.1% of all malignancies of the esophagus take this form. The average age of diagnosis is about 65 years, two thirds of patients are men, and the prognosis is very poor. The tumor is mostly located in the middle third (52%) and, in about 35% of cases, the lower third.
In more than 90% of cases there is a history of smoking, and in about 70% a history of alcohol use. The median survival of patients with small cell carcinoma of the esophagus is about 11 months, and the 2-year survival rate is about 25%.
Malignant Melanoma of the Esophagus
Primary esophageal melanoma is a very rare malignancy, with only 300 reported cases, making up about 0.1 to 0.5% of all esophageal malignancies. It has a very poor prognosis, with very early metastasis.
Melanocytosis at the basal layer of the esophageal epithelium, caused by chronic esophagitis or basal cell hyperplasia, is thought to play an important role in its pathogenesis. The tumor is more common in men and is mostly diagnosed close to 60 years of age.
The most common symptom is dysphagia, but in more than 90% of cases it is very delayed, because the melanoma is soft. The primary lesion is mostly located in the middle and distal third, and it can be dark depending on the amount of melanin, or even amelanotic. Because melanin expression varies, a melanoma with little melanin has a high chance of being misdiagnosed as a poorly differentiated carcinoma.
Satellite lesions may appear a few centimeters from the primary lesion, thought to be produced by intramural metastasis. Age, stage and lymph node involvement all affect prognosis, and the calculated 5-year survival is estimated to be around 37%.