Primary retroperitoneal squamous cell carcinoma: a case report with review of the literature.

Squamous cell carcinoma originating in the retroperitoneal cavity is an exceedingly rare disease, and little is known about it. Here, we report the case of primary retroperitoneal squamous cell carcinoma. A 76-year-old gravida four para two woman with a history of hysterectomy for unknown reasons was referred to our hospital for an infant-head-sized multicystic pelvic mass. She was initially diagnosed with ovarian cancer Stage IIB, poorly differentiated carcinoma by exploratory laparotomy in which only a tumor biopsy was performed due to severe adhesion. She underwent 5 courses of combination chemotherapy with paclitaxel and carboplatin, which reduced the tumor from 14 to 6.5 cm. Interval debulking surgery proved that the tumor was in the retroperitoneal cavity and not associated with the ovaries. She was finally diagnosed with squamous cell carcinoma originating in the retroperitoneal cavity. Human papilloma virus type 16 was identified using polymerase chain reaction. Three more courses of paclitaxel and carboplatin were administered, and she has been without evidence of disease for 6 months. A comprehensive literature search identified seven similar cases of which four individuals had a history of abdominal hysterectomy. Four out of the seven cases were tested for the presence of P16, two for HPV; all the results were positive. These findings suggest that HPV could be the cause of squamous cell carcinoma on the pelvic peritoneum, and that past hysterectomy is a possible contributing factor.