1675 A Rare Case of Rectal Adenocarcinoma With Isolated, Asynchronous Metastasis to the Temporal Bone

Abstract

INTRODUCTION: Metastatic disease only to the bone without other organ involvement in colorectal cancer patients is extremely rare. Isolated, asynchronous metastasis to the temporal bone, without involvement of the liver or lung is an even further deviation from the traditional presentation. We present the case of a 56-year-old lady with a history of rectal cancer in remission presenting with hearing loss, facial swelling, and facial droop. CASE DESCRIPTION/METHODS: The patient presented with a stage 3C rectal cancer pT3N2bM0 and received adjuvant chemotherapy based on her pathology. The disease was in complete remission, without evidence of any CT, PET, or endoscopic findings of disease recurrence. Three years after her initial diagnosis, the patient began to develop swelling, with associated myalgia and hearing loss on the ipsilateral side. CT and MRI imaging revealed a mass in the right temporal bone, eroding into the bony architecture with peri-orbital and temporal swelling, with inflammatory changes of the right mandibular process. A subsequent biopsy of the cranial mass was consistent with metastatic rectal adenocarcinoma. Repeat imaging had not shown any evidence of abdominal or chest disease. DISCUSSION: More than 90% of colorectal carcinomas are adenocarcinomas originating from epithelial cells of the colorectal mucosa. Approximately 10% of all colorectal carcinomas are mucinous carcinomas. The metastatic pattern of colorectal carcinomas is well known. In a study using more than 49,000 patients with colorectal cancer, it was found that the most common sites of metastasis involved the thoracic organs, the liver, the nervous system, and the peritoneum. Literature review reveals an overall incidence of 5–11% of bony metastasis. This figure includes both isolated skeletal metastases and those with coinciding liver and lung spread. Isolated skeletal metastases are even more infrequently seen, occurring at an estimated frequency of 1–2%. Asynchronous and isolated metastasis to the temporal bone is rare. Assi R, Mukherji D, Haydar A, Saroufim M, Temraz S, Shamseddine A. Metastatic colorectal cancer presenting with bone marrow metastasis: a case series and review of literature. J Gastrointest Oncol. 2016;7(2):284–297.