A 53-year-old man self-refers to dermatology for evaluation of a lesion on his left maxilla that has been basically unchanged for several years. He is concerned for two reasons: First, it is a rare day on which he fails to cut the lesion while shaving, and he is afraid this repeated trauma will “turn it into skin cancer.” Second, a co-worker who recently had a basal cell carcinoma diagnosed in the same location constantly asks the patient when he is “going to see someone about that lesion.”

Additional history taking reveals that the patient has had little sun exposure in his life. He is otherwise healthy.

Examination of the lesion shows a nevoid pink 6-mm intradermal nodule in the lower left nasolabial/upper maxillary area. Closer inspection reveals that the surface of the lesion is totally smooth and devoid of adnexae (pores, hairs). On palpation, the lesion is notably firmer than expected. The lesion has a slightly translucent appearance, almost as if light could pass through it.

ANSWER
The best answer is to send the slides to a dermatopathologist (choice “a”), for reasons that will become clear in the discussion. It is true that by re-excising with margins (choice “b”), the lesion would certainly be gone, but that does nothing to address the potential pathologic implications of some of the items in the differential diagnosis for this type of lesion.

The same could be said for rechecking the lesion periodically (choice “c”), which would otherwise be an intelligent option. It is almost never wrong to consult with a supervising/collaborating physician (choice “d”), but that does not relieve the PA/NP of the ultimate responsibility for resolving the dilemma.

DISCUSSION
Odd little papules in the nasolabial fold can have implications far beyond the usual “benign versus malignant” issue. With its surface devoid of adnexal structures, and firm feel, this lesion was a bit suspicious, history of stability notwithstanding.

Generally termed skin adnexal tumors (SATs), these lesions are derived from local adnexal structures, such as eccrine or apocrine sweat glands or pilosebaceous unit tissue. But they may originate from pluripotent stem cells located in the outer root sheath of the hair follicle, residing in an area called “the bulge.”

Their final designation is based on the predominant cell type seen on pathology, but differentiation can be difficult, even for experienced pathologists. Many benign types have been described, but for every benign category, a malignant counterpart exists. The latter tend to be aggressive and involve nodes, metastasis, and generally poor outcomes.

Heredity, skin type, and UV exposure play significant roles in some types of skin cancer, but an intracellular signaling pathway is also thought to determine the ultimate differentiation of these cells. Loss of inhibition of this pathway, which normally occurs, is apparently the main deciding factor in malignant transformation.

But the importance of a precise diagnosis for an SAT is more than mere benign versus malignant considerations. These lesions can serve as markers for syndromes associated with internal malignancies, such as Cowden’s disease (trichilemmomas) or Muir-Torre syndrome (sebaceous neoplasm), to name just two.

The person most likely to be able to discriminate between these various possibilities is the dermatopathologist, who is not only an expert in what is seen microscopically, but is also typically a practicing dermatologist who regularly sees the conditions he diagnoses. The biopsying provider has an obligation to insist on a crystal-clear diagnosis, when it can be obtained. And that “diagnosis” isn’t always about what the lesion is. Sometimes it’s as much about what the lesion means.           

SUGGESTED READING
Alsaad KO, Obaidat NA, Ghazarian D. Skin adnexal neoplasms—part 1: an approach to tumours of the pilosebaceous unit. J Clin Pathol. 2007;60(2):129-144.