Many patients with ugly and obviously unhealthy nails consider this a cosmetic issue and put off the visit to a doctor till a better time. Is there a time when you absolutely must be seen by a doctor? The following two nail diseases should be considered as a late notice.
SCC in situ presents as flesh-colored or hyperpigmented verrucous papules or plaques with either keratosis or hyperkeratosis. The lifting of the nail plate (Onycholysis) can occur. Invasive SCC can begin as bone pain but is most commonly depicted as a slow-growing solitary subungual or periungual nodule that ulcerates and/or bleeds and likely destroys the nail.
Subungual SCC is the most common malignant tumor of the nail. Fingers are more likely to be involved (especially the first and fourth digits). Metastasis to the bone occurs 20%-55% of the time. Proximal and lateral nail plates, the nail matrix, and the hyponychium are affected (more about nail anatomy). Human papillomavirus (HPV) type 16, 18, 34, or 35 is detected in more than 60% of cases. HIV-positive patients are especially susceptible to developing HPV-associated squamous cell carcinoma. Cancer in this area is rare and usually a result of prior radiation therapy, but the prognosis is good when compared with that of SCC in other cutaneous sites.
Nail biopsy is necessary to make the diagnosis of subungual SCC. Mohs micrographic surgery is employed with noninvasive disease; the cure rate is around 96%. When bone is involved, amputation of the affected digit and/or radiation therapy can be used to destroy the unresectable tumor. If you are faced with a nail problem or lesion that won’t go away, consider a biopsy to rule out underlying subungual SCC.
- Peak incidence: 50-70 year old African Americans, Asians, and Native Americans.
- Looks like: brown-to-black pigmented nail band with blurred borders.
- Change in size of the nail band: recent, rapid, and sudden.
- Digit most commonly involved on hands or feet: first, followed by the hallux and second digit. Dominant hand more often involved, single digits more common than multiple digits.
- Extension of pigment into proximal or lateral nail plate (Hutchinson’s sign).
- Family or personal history of dyplastic nevus syndrome or previous melanoma.
Melanoma looks like a pigmented lesion that arises subungually or periungually and/or as a dystrophic nail plate, which developed after a traumatic incident.
Subungual melanomas represent 0.7%-3.5% of all melanomas. Five-year survival rates range from 16% to 87%, depending on extension/depth of the tumor. Amelanotic lesions account for 25% of cases.
Pyogenic granuloma shares some of the same characteristics as subungual melanoma. Both are dark-appearing growths. However, pyogenic granulomas are more papular; well-defined; fluctuant; sometimes tender; and a deeper, violaceous color similar to thrombosed blood.
Treatment: Biopsy is required to determine the extent of disease. When involvement is localized, surgical removal with clear margins is sufficient. More widespread involvement can be treated with amputation of the affected digit with or without systemic chemotherapy and use of interferon.