Colonic medullary carcinoma: an exceedingly rare type of colorectal malignancy: a case report and review of the literature.

BACKGROUND: Medullary carcinoma of the colon is a rare subtype of colorectal cancer that has a unique, and sometimes varied, clinical and histologic profile. It usually presents in adult patients older than 50 years. Here, we report a unique case of young male patient who initially presented with abdominal pain followed by a large bowel obstruction.

CASE PRESENTATION: A 40-year-old SriLankan male presented with right-sided abdominal pain and on examination, there was a palpable right iliac fossa mass. Colonoscopy and a computed tomography scan revealed cecal mass. Later, while waiting for elective resection, the patient developed symptoms and signs of a large bowel obstruction. He underwent a laparoscopic right hemicolectomy with an uneventful postoperative course. The histopathologic evaluation of the resected specimens showed invasive carcinoma with syncytial growth pattern, foci of lymphoid host response, and dirty necrosis, in keeping with a medullary carcinoma pT4a pN2b. Unlike most reported medullary carcinoma cases, this patient was young and caudal-related homeobox transcription factor 2 positive.

CONCLUSION: We have reported another case of medullary carcinoma of the colon in a young patient with unique histologic characteristics. Reporting such cases helps in refine understanding of the histologic and genetic, as well as clinical, phenotypes of medullary carcinoma of the colon.