nevus sebaceus of Jadassohn with malformed sweat glands

NEVUS SEBACEUS OF JADASSOHN (NSJ) CONTAINING MALFORMED SWEAT GLANDS

This 37 yr. old female had a bald spot on the scalp since infancy, and the surface became rough during puberty. This history is characteristic of NSJ. Other examples of NSJ (face and scalp) have been discussed and defined elsewhere.

Sweat gland (unit) tumors, particularly of apocrine derivation, are well-documented in NSJ. Sweat gland malformations have received little attention as such. This emphasis is consistent with that placed on tumors of the other pilosebaceous components rather than on the malformations. Sweat glands that have combined eccrine and apocrine features are occasionally seen in NSJ. One could postulate apocrine metaplasia in eccrine glands or eccrine metaplasia in apocrine glands. It is more palatable to me to consider these to be malformed or incompletely differentiated apocrine glands that failed to regress. Another alternative would be to deny the existence of the obvious.

Scan power view of the biopsy. Epidermal hyperplasia could be construed as hyperplasia of follicular infundibular epithelium. There may also be a component secondary to picking. Sebaceous hyperplasia is absent in this biopsy. Sweat glands (units) are abnormally prominent, and some are cystically dilated.

Medium power view of the area in the square depicted above. This is a malformed hair follicle. Hyperplasia of the basaloid follicular epithelium can be misinterpreted as basal cell carcinoma. Similar hyperplasia is sometimes seen over dermatofibromas.

Medium power view of one of the sweat glands. Apocrine type snouts (APO) are found in part of the sweat gland, but cells of the type more commonly found in eccrine sweat glands (ECC) are also present.

Medium power view of another sweat gland. There is an odd type of differentiation that could be construed as being secondary to the malformation.

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	Scan power view of the biopsy. Epidermal hyperplasia could be construed as hyperplasia of follicular infundibular epithelium. There may also be a component secondary to picking. Sebaceous hyperplasia is absent in this biopsy. Sweat glands (units) are abnormally prominent, and some are cystically dilated.
	Medium power view of the area in the square depicted above. This is a malformed hair follicle. Hyperplasia of the basaloid follicular epithelium can be misinterpreted as basal cell carcinoma. Similar hyperplasia is sometimes seen over dermatofibromas.
	Medium power view of one of the sweat glands. Apocrine type snouts (APO) are found in part of the sweat gland, but cells of the type more commonly found in eccrine sweat glands (ECC) are also present.
	Medium power view of another sweat gland. There is an odd type of differentiation that could be construed as being secondary to the malformation.