Minimal Spinal Dysraphism vs. Dermal Sinus of the Coccyx
Left picture: The most probable clinical diagnosis is a minimal spinal dysraphism. Additional examinations are indispensable and, if the diagnosis is confirmed, a surgical revision is indicated. Right picture: Here, the diagnosis is a coccygeal dermal sinus, with neither a relation nor continuation to the spine and the spinal channel. This disease entity is relatively frequent; due to the local danger of infection, excision of the anomaly is indicated in deep and narrow types (in contrast to superficial and broad lesions). It should not be mixed up with the so-called pilonidal sinus of adulthood (= so-called jeep disease) which is an acquired lesion. For the differentiation between minimal spinal dysraphism and coccygeal dermal sinus, not the aspect of the local findings is of significance, but the site over the sacrum or the coccyx; in minimal spinal dysraphism, a simple dermal sinus over the sacrum is also possible as local finding.
Left picture: A depression of the skin is visible which reminds of a navel. It lies over the sacrum of this 1.1-year-old boy. Right picture: 10-month-old infant with a skin retraction in the analogous region as in the contralateral case. On looking closely, the aspect of the local findings is somewhat different and lies asymmetrically in the neighborhood of the tip of the coccyx.