Anterior abdominal wall metastasis following curative resection and chemoradiation of rectal cancer masquerading as a desmoid tumour: A clinical conundrum

Abstract

Desmoid tumour of the anterior abdominal wall (rectus sheath) commonly occurs in women post abdominal surgery. Metastasis from colorectal cancer to the anterior abdominal wall, on the other hand, is rare and produces a complex management dilemma. This Case study presents a 57-year-old woman who received a curative laparoscopic low anterior resection and adjuvant chemoradiation in 2013. Seven years later, she presented with an asymptomatic anterior abdominal wall lump. Clinically, the lump appeared to be a desmoid tumour. A wide local excision of the lump was carried out and the final histopathology showed a metastatic lesion (adenocarcinoma). With adjuvant chemotherapy, the patient is now disease-free and doing well. A possibility of distant metastasis must be kept in mind for all patients, even when they have undergone curative resection with adjuvant chemoradiation for colorectal cancer.

Keywords: Adenocarcinoma; Chemoradiation; Colorectal cancer; Desmoid tumour; Laparoscopic low anterior resection.

Figure 1

PET scan (A) axial and (B) coronal view of the hypermetabolic anterior abdominal mass.

Figure 2

Resected tumour specimen.

Figure 3

Photomicrograph showing invasive tumour composed of irregular, enlarged glands lined by mucin depleted pleomorphic columnar cells with nuclear stratification and luminal necrotic debris surrounded by desmoplastic stroma (200×).