Primary squamous cell carcinoma of the colon: A rare case report

Abstract

Introduction and importance: Squamous cell carcinoma (SCC) of the colon is an extremely rare pathologic entity, accounting for less than 1 % of all colorectal cancer cases. They tend to be very aggressive with poor outcomes and treatment strategies are still controversial due to the paucity of data available to guide management.

Case presentation: A case of a cecal mass with metastatic liver lesions. Initially diagnosed as an adenocarcinoma, the patient underwent resection with metastasectomy. Despite achieving negative surgical margins and undergoing adjuvant chemotherapy, the patient relapsed and presented with a new mass in the descending colon. The patient underwent resection with subsequent follow-up revealing distant metastasis. The patient passed away soon after.

Clinical discussion: Primary colorectal SCC has similar presentation to adenocarcinoma of the colon. Unfortunately, it usually presents at a late stage. Diagnosis of colorectal SCC requires histologic confirmation of SCC plus exclusion of possible causes. Management is predominantly definitive radical resection followed by adjuvant chemotherapy and radiotherapy. Surgical margins should be at least 5 cm, preferably 10 cm. Lymph node yield greater than 20 was associated with improved survival. Studies assessing the prognosis of primary colorectal SCC following chemo-radiotherapy have not been done.

Conclusion: Surgery remains the most vital important step in the management of colonic SCC. The role of chemotherapy and/or radiation remains questionable. Depending on the aggressiveness of this disease the need for further frequent.

Keywords: Colon; Primary; Squamous cell carcinoma; Therapeutic.

Fig. 1

Coronal CT scan post contrast revealing an ascending colon mass (yellow arrow).

Fig. 2

Coronal CT scan of the abdomen and pelvis showing a mass in the liver, suggestive of metastases.

Fig. 3

Axial CT scan of the abdomen and pelvis showing the descending colonic mass with near complete obstruction of the inner lumen (red arrow).

Slide 1

Descending colon mass with hematoxylin and eosin (H&E) staining. (a) Low power view showing invasive cords and nests of poorly differentiated squamous cell carcinoma associated with a desmoplastic stroma and presence of tumor necrosis (5×). (b) High power view showing tumor cells with atypical vesicular nuclei, conspicuous nucleoli, and prominent mitotic activity (20×).

Slide 2

P 40 immunohistochemical stain showing nuclear positivity of the tumor cells (10×) – Inset: P40 positive control.

Slide 3

CK 5/6 immunohistochemical stain showing cytoplasmic positivity of the tumor cells (10×) – Inset: CK 5/6 positive control.

Slide 4

CDX2 immunohistochemical stain showing nuclear focal weak positivity of the tumor cells (10×) – Inset: CDX2 positive control.

Slide 5

CK20 immunohistochemical stain showing cytoplasmic negativity of the tumor cells (10×) – Inset: CK20 positive control.

Slide 6

CK7 immunohistochemical stain showing membranous/cytoplasmic negativity of the tumor cells (10×) – Inset: CK7 positive control.

Slide 7

Previous ascending colon mass with hematoxylin and eosin (H&E) staining, showing malignant glands with a complex architecture alongside a squamous component (5×).