Repigmentation of Grey Hair is an Important Sign to Know
There are many reasons why hair might repigment. Authors of recent publication report a case of scalp hair re-pigmentation as a feature of lentigo maligna (LM). LM is a variant of melanoma in situ that develops on chronically sun-damaged skin. Occasionally this tumor also invades hair follicles.
Gressler et al 2022
The patient was an 85-year-old man with a history of chronic lymphocytic leukemia and chronic myeloid leukemia. He sought medical attention for a change in the right parietal scalp. His history included prior melanoma in situ and non-melanoma skin cancer. The patient reported hair darkening on the right scalp for several months. He denied an underlying skin lesion.
Examination of the scalp revealed grey-white hair throughout except for a 0.5 cm ill-defined light brown macule with an overlying 4.5 x 3.0 cm patch of brown hair in the right parietal area Shave biopsy was performed with a resulting diagnosis of melanoma in situ, lentigo maligna type. A wide local excision was performed as definitive treatment.
The authors propose that re-pigmentation of previously white or gray hair should rise suspicion for lentigo maligna on the scalp
Several prior studies have supported the notion that re-pigmention of grey/white hair may be a sign of melanoma especially lentigo maligna in both men and women.
Lackey et al 2019
In 2019, Lackey et al published a nice report of an 86-year-old white referred regarding a 15-cm × 8-cm patch with brown and black pigmentation occupying the vertex and superior occipital scalp. Similar to The Gressler et al study, the lesion included repigmented black hairs. It was was confirmed to be a lentigo maligna.