Rectal tumor associated with achondroplasia and Down syndrome: A case report

Introduction.Some manifestations of Down syndrome overlap with those of achondroplasia. Simultaneity of both Down syndrome and achondroplasia in an individual is extremely rare (1 in every 25,000,000 births). Moreover, the cancer incidence of people with intellectual disabilities has been poorly documented. We are presenting this rare case, due to lack of any documented reports on the co-occurrence and management of Down syndrome, achondroplasia and anal tumor.Case presentation.A 19 year-old woman was presented to our care by her parents complaining from anal bleeding and mass in this location. She was a down syndrome and achondroplasia patient who had the history of hospitalization for rectorrhagia and rectum prolapse twice. Colonoscopy and polypectomy was done then, and the diagnosis was familial adenomatous polyposis (FAP). In physical examination, the abdomen was soft and there were no tenderness, rebounding or guarding. In addition, a perianal bleeding mass was protruded from her anus. The mass size was about 5*5 cm2 and its surface was necrotized. Abdominoperineal resection surgery (APR) and Polypectomy were done. She was diagnosed with poorly differentiated neuroendocrine carcinoma (small cell type). The tumor invaded anal sphincter, muscularis propria and subserosal tissue. Chemotherapy was prescribed starting with pediatric dosage of cisplatin and Etoposide but it was increased to adult dosage. After six sessions of chemotherapy, suddenly she developed tumor lysis syndrome (TLS). Despite starting treatment immediately, she could not tolerate the treatment. She expired due to septic shock, infection and hypotension. Discussion.Acute rectorrhagia and bleeding are the indications of APR surgery although Chemo-radiation therapy is the standard treatment at the beginning. Dosage adjustment for this patient was a challenge. Due to Achondroplasia and her small stature, the chemotherapy dosage was started with children dosage. She was not responsive to therapy and was older than 18 so the adult dosage was prescribed.

Keywords:

Achondroplasia , Down Syndrome , Rectal Neoplasms , Anus Neoplasm , Gastrointestinal Hemorrhage.