Interesting case of an abdominal wall Merkel cell carcinoma highlighting the importance of developing an Australian clinical practice guideline

Abstract

A 66-year-old Australian male farmer was referred for management of an asymptomatic, rapidly expanding, anterior abdominal wall mass. It was firm and well circumscribed. There were no overlying skin changes, constitutional symptoms or weight loss. His medical history included small bowel obstruction and resection from a Meckel's diverticulitis and a 40-pack-year smoking history. Core biopsy was suggestive of a neuroendocrine tumour and Gallium-68-Dodecane-Tetraacetic-Acid (68GaTate) positron emission tomography revealed an avid solitary lesion confined to the subcutaneous space in the left anterior abdominal wall. Wide local excision was performed, and histopathology revealed Merkel cell carcinoma (MCC). Although classically regarded as a primary cutaneous neuroendocrine tumour, MCC may originate from the subcutaneous fat without obvious skin involvement. Older patients with asymptomatic, rapidly enlarging lesions, particularly if immunosuppressed, with significant ultraviolet sunlight exposure, should raise a high index of suspicion for MCC. Like melanoma, non-metastatic MCC should be treated aggressively for best prognosis.

Keywords: dermatology; general surgery; plastic and reconstructive surgery; surgical diagnostic tests; surgical oncology.

Figure 1

Top left image—sagittal slice of CT scan demonstrating subcutaneous soft tissue mass in abdominal wall. Top right image—axial slice of CT scan demonstrating subcutaneous soft tissue mass in left abdominal wall. Bottom left image—sagittal slice of 68GaTate positron emission tomography/CT (PET/CT) demonstrating an intensely 68GaTate avid subcutaneous soft tissue lesion in anterior abdominal wall. Bottom right image—axial slice of 68GaTate PET/CT demonstrating an intensely 68GaTate avid subcutaneous soft tissue lesion in left anterior abdominal wall.