Rare squamous cell carcinoma arising from a presacral epidermoid cyst: A case report

Abstract

Introduction: Presacral epidermoid cysts are uncommon, usually benign cysts caused by developmental abnormalities in the fetal period. We present a rare case of squamous cell carcinoma arising from a presacral epidermoid cyst.

Presentation of case: A 59-year-old woman complained of tenesmus and discomfort in the buttocks. Computed tomography revealed a 50-mm well-defined cystic mass in the presacrum and a 70-mm solid mass extending from the cyst into the rectum, vagina, and left sciatic spine. On T1-weighted magnetic resonance images, the cyst was unilocular and the mass was marginated with low intensity. On T2-weighted images, the mass had high intensity. A malignant presacral developmental cyst was diagnosed, without obvious metastasis. Using abdominal and parasacral approaches, Hartmann's operation was performed with multiorgan resection, including the sacrum, coccyx, left sciatic spine, internal obturator muscle, rectum, and uterine appendage. Histopathology of the excised specimen revealed a squamous cell carcinoma originating from the presacral epidermoid cyst.

Discussion: Reports of malignant transformation of epidermoid cysts in the presacral space, as in the present case, are extremely rare. Because of their unusual location and slow growth, epidermoid cysts tend to remain asymptomatic. Because the patient had a malignant tumor with suspected invasion of adjacent organs, combination surgery was selected.

Conclusion: Although further research is required, presacral epidermoid cysts are extremely rare and may be malignant. Thorough preoperative image evaluation is crucial for complete resection.

Keywords: Benign cysts; Fetal period; Presacral epidermoid cysts; Squamous cell carcinoma.

Fig. 1

Colorectal examination shows exudation from the outside rectal wall, and a rectal submucosal tumor was suspected. No erosion or ulceration is seen on the mucosal surface.

Fig. 2

Contrast computed tomography reveals a 50-mm well-defined cystic mass in the presacrum (arrowhead) and a 70-mm solid mass extending from the cyst into the rectum, vagina, and left sciatic spine (arrow) (A). The solid mass demonstrates high fluorodeoxyglucose uptake on positron emission tomography (B).

Fig. 3

T1-weighted magnetic resonance image shows a unilocular cyst and marginated low-intensity mass (arrowhead) (A). T2-weighted magnetic resonance image shows a high-intensity mass (arrowhead) (B). A solid mass with a contrast effect is found on the left side and head side of the cyst in the T2-weighted magnetic resonance image. The solid part touches the rectum, vagina, and left sciatic spine, with possible invasion (arrow). The cyst does not involve the levator ani muscle in the coccyx and sacrum (arrowhead) (C: Coronal section, D: Sagittal section).

Fig. 4

Macroscopic examination. Resected rectum including the tumor, sacrum, coccyx, and uterine appendage (A). Macroscopic examination of the resected specimen reveals a tumor composed of a 50-mm cyst (arrowhead) and an 80-mm solid lesion (arrow) in the front of the sacrum and coccyx. No skin appendages are seen in the cyst. The cut surface of the solid lesion reveals grayish white tissue (B). Microscopic examination. The luminal surface of the cyst is covered with squamous epithelium (hematoxylin-eosin stain, ×200 magnification) (C). Continuous invasion and growth of the squamous cell carcinoma seen from the strong atypical cells of cysts to the solid part (hematoxylin-eosin staining, ×100) (D).