PMC4736194_01
(a) Abdomen and pelvis CT showing a heterogenous mass with cystic and solid component. (b) Colon biopsy (H&E, 40x) showing a dysplastic squamous cell epithelium with keratin material, suspicious for squamous cell carcinoma. (c) Gross picture showing a cystic teratoma with sebaceous material and hair (right), the colon (left), and a firm white tan mass in between. (d) Squamous cell carcinoma (inferior left) invading into the colonic wall up to the submucosa (H&E, 20x). (e) P63 immunostain highlighting the tumor (20x). (f) Negative p16 immunostain (20x). (g) In situ squamous cell carcinoma (H&E 20x). (h) In situ squamous cell carcinoma with invasive component (H&E, 10x).
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fig1
A computed tomography scan of the abdomen and pelvis demonstrated a large 18.9 x 12.8 x 12.5 cm heterogeneous mass originating either from the right adnexa or the intestine (Figure 1(a)). The colonic biopsy showed minute detached fragments of dysplastic squamous epithelium, highly suspicious for squamous cell carcinoma (Figure 1(b)). The cyst was filled with tan sebaceous material and black hair and was attached to the colonic wall, where a firm white 11 cm solid mass was noted (Figure 1(c)). Microscopic examination revealed an invasive moderately differentiated keratinizing squamous cell carcinoma invading up to the submucosa of the colon (Figure 1(d)). The cystic component shows a mature teratoma with in situ carcinoma in a squamous-lined cyst (Figures 1(d), 1(g), and 1(h)). The tumor cells were positive for p63 (Figure 1(e)) and negative for p16 (Figure 1(f)) by immunohistochemistry.
PMC4736194_02
(a) Pelvis CT showing a mass with a cystic and solid component and internal septations. (b) Colon biopsy revealing an atypical squamous epithelium, suspicious for well-differentiated squamous cell carcinoma (H&E, 40x). (c) Gross picture showing a cystic ovarian mass (right) and (d) squamous cell carcinoma invading colonic wall (H&E, 20x). (e) In situ squamous cell carcinoma (H&E, 10x). (f) In situ squamous cell carcinoma and invasive component (H&E, 10x).
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fig2
No colonic mucosa was present (Figure 2(b)). Upon opening, the segment of colon showed a large fistulous tract that measures 2 cm in diameter (Figure 2(c)). Microscopic examination revealed a moderately differentiated squamous cell carcinoma invading up to submucosa of the colon (Figure 2(d)) and an in situ squamous cell carcinoma component in the lining of the ovarian cyst (Figures 2(e) and 2(f)).