Primary Squamous Cell Carcinoma of the Sigmoid with a Colovesical Fistula: A Rare Case during the COVID 19 Pandemic

Primary colonic squamous cell carcinoma is an exceptionally rare clinical pathology with an overall estimated incidence of 0.06%.

This is a case of a 62 year old female with a three-month history of left lower quadrant pain associated with weight loss. Colonoscopy revealed a non-obstructing fungating mass at the sigmoid colon noted to be 20cm from the anal verge with biopsy of squamous cell carcinoma. CT scan showed a complex mass of the sigmoid colon with a colovesical fistula. Elective surgery was advised but the patient subsequently refused treatment due to the fear of contracting COVID 19.

Primary squamous cell carcinoma of the colon is a rare spectrum of pathology that warrants further investigation. The COVID 19 pandemic has had a great psychological impact increasing fear and anxiety in cancer patients disrupting the continuum of cancer care leading to delays in both diagnosis and treatment.

Colonic squamous cell carcinoma; Colovesical fistula; COVID 19 pandemic

Primary colonic squamous cell carcinoma is an exceptionally rare clinical pathology with an overall estimated incidence of 0.06% [1]. It represents 0.5% of all colorectal tumors with less than 150 cases reported in literature [2]. The incidence of squamous cell carcinoma of the colon and rectum has been reported to be 0.25 to 0.1 per 1,000 colorectal carcinomas [3].

There has been no known published documentation of primary colonic squamous cell carcinoma in the Philippines.

A 62-year old female with a three-month history of progressive left lower quadrant pain associated with weight loss and decrease in stool caliber. A colonoscopy was done which showed a non-obstructing fungating mass at the sigmoid colon noted to be 20cm from the anal verge (Figure 1). Biopsy of the mass revealed Squamous Cell Carcinoma, Keratinizing. CT scan of the whole abdomen with contrast showed a 7.8×8.6×8.2 cm heterogeneously enhancing complex mass of the sigmoid colon, 3.6 cm in greatest thickness, with no enlarged retroperitoneal, mesenteric, or pelvic lymph nodes seen. An incidental finding of a 1.2×1 cm small colovesical fistula was noted at the sigmoid colon communicating into the urinary bladder (Figure 2). A cystogram was done which revealed no extravasation of dye towards the colon. Cystoscopy was done with no masses seen within the bladder; furthermore, the fistula was not visualized. A CT scan of the chest was done which revealed unremarkable results.

A slide review was done at a separate institution which revealed the same result of invasive squamous cell carcinoma, keratinizing (Figure 3). The smear showed fragments of malignant neoplasm composed of atypical epithelial cells arranged in nests and sheets. The tumor cells had pleomorphic round to ovoid nuclei, some with visible nucleoli, and abundant eosinophilic cytoplasm exhibiting squamous differentiation and individual cell keratinization. Intracellular bridges were identified within some cell groups. Occasional parakeratotic cells were seen. Mitotic figures were rare. The supporting stroma was infiltrated with lymphocytes and plasma cells. A single fragment of benign colonic mucosa was also identified.

Figure 1: Colonoscopy showing a fungating mass at the sigmoid colon.

Figure 2: CT scan of the whole abdomen with contrast showing the sigmoid mass and colovesical fistula on coronal section.

Figure 3: Section of the mass on hematoxylin and eosin stain at high power field magnification.

The patient was noted to be average built with normal systemic examination findings. There was no skin lesions noted. The gynecologic exam revealed a normal cervical contour.

The patient was advised for elective surgery but subsequently refused treatment and was lost to follow up due to the fear of contracting COVID 19 within the hospital premises.

Squamous Cell Carcinoma (SCC) of the colon is an extremely rare and aggressive neoplasm that has a relatively poorer prognosis as compared to that of adenocarcinoma [4]. Before a diagnosis of primary squamous cell carcinoma of the colon or rectum is made; a criterion must be fulfilled as given by Williams et al. in 1979. This criterion should encompass the following: (A) absence of evidence of squamouscell carcinoma of any other part of the body, ruling out any chance of possible metastasis from any organ to the colorectal site; (B) exclusion of any proximal extension of anal squamous cell carcinoma; (C) absence of fistulous tract lined by squamous cells; and (D) confirmation of squamous cell carcinoma by histological analysis [5]. All of these criteria were fulfilled by our case.

Management of these cases is difficult due to its rarity. However, surgical resection and adjuvant chemotherapy is deemed an acceptable therapeutic approach [6]. The patient was appraised for surgery but refused due to the fear of contracting COVID 19 during hospitalization. The COVID 19 pandemic has had a great psychological impact increasing fear and anxiety in cancer patients disrupting the spectrum of cancer care leading to delays in both diagnosis and treatment [7,8].

Primary squamous cell carcinoma of the colon is a rare spectrum of pathology that warrants further investigation. Early detection accompanied by close patient follow up is essential to the care of patients with this histological diagnosis since there has been no established clinical protocol for its management.