The nail matrix is the layer of keratin-producing cells at the base of each toe or finger. As new cells arise, the hard husks of older cells are pushed forward, creating the nail plate – what we think of as just the nail itself. Because, like cancer cells, nail matrix cells divide rapidly, many chemo drugs can impair their functioning. The nail matrix and the tissue below the nail plate – the nail bed – also contain many blood vessels. Chemo drugs can damage blood vessels in a number of ways, but perhaps the most common mechanism for this is by increasing the risk of developing blood clots. Melanonychia is known to occur in patients taking cyclophosphamide, which is one of the six drugs given to the patient.
As the authors pointed out to Live Science, many chemotherapy agents are associated with melanonychia, Meuhrcke’s lines, and Mees’ lines, and “it is not uncommon to have one [type of] nail change." But, "having three changes at the same time is rare."
A variety of conditions and treatments induce alterations to nail appearance and integrity, and physicians often use these signs as indicators of their patient’s state of health. According to the Mayo Clinic, there are at least seven additional distinctive nail irregularities linked to diseases and injuries, ranging from kidney failure, mineral deficiencies, and hypothyroidism.
After six rounds of a mixed chemotherapy regimen, the patient achieved remission from his non-Hodgkin’s lymphoma. About six months after the last cycle, his fingernails had returned to normal.
[H/T: Live Science]