[Sacrococcygeal dermal sinus presented bacterial meningitis: a case report].

A rare case of sacrococcygeal dermal sinus suffering from relapsing meningitis is presented. In addition, deference of clinical figure and pathology between sacrococcygeal region and other regions are discussed. A 10 -month-old boy was suffering from relapsing meningitis. Spinal MRI was performed to find occult spinal dysraphism because he had a pit on his hip. The MRI revealed sacrococcygeal dermal sinus. He received surgical resection of dermal sinus based on this findings. Interestingly, different from other dermal sinuses, the dermal sinus runs to caudal direction, and was fused filum terminale with dermoid cyst. This interesting pathological feature of sacrococcygeal dermal sinus seems to come from developmental difference between sacrococcygeal dermal sinus and the other dermal sinuses. Only sacrococcygeal dermal sinus is related with caudal cell mass on its pathogenesis. Because filum terminale is also developed from caudal cell mass, sacrococcygeal dermal sinus seems to be related with filum terminale. Most important differential diagnosis is coccygeal pit that is found in 1 -4% of newborn baby. The clinical feature and pathology got from our case must be very helpful to distinguish sacrococcygeal dermal sinus from coccygeal pit.