Laugier-Hunziker syndrome is characterized by idiopathic mucocutaneous pigmentation that may be associated with longitudinal melanonychia. The significance of this condition is due to its inclusion in differential diagnoses of pigmentary disorders of the oral mucosa, especially Peutz-Jeghers syndrome.

To cite: Khan K, Mavanur AA. BMJ Case Rep Published online: [please include Day Month Year] doi:10.1136/bcr-2015213459 DESCRIPTION An otherwise healthy 13-year-old boy was noted to have a discolouration arising from the nail bed of the left thumb. The lesion exhibited brisk linear transformation since it was initially noticed 4 months prior. There was no family history of melanoma, and he was n...

Figure 1. Photograph showing longitudinal black bands on the nails of 2 fingers (thumb and index) of the right hand Diagnosis: HIV-1 infection and longitudinal melanonychia. This diagnosis was suggested by the findings of the physical examination (figure 1) and laboratory data in conjunction with the sexual history of the patient's husband, who admitted on further questioning that he was sexual...

Longitudinal melanonychia can be caused by melanocyte activation (hypermelanosis) or proliferation (lentigo, nevus or melanoma). Histopathologic examination is mandatory for suspicious cases of melanomas. Tangential biopsy of the matrix is an elegant technique avoiding nail plate dystrophy, but it was unknown whether the depth of the sample obtained by this method is adequate for histopathologi...

Occurrence of squamous cell carcinoma (SCC) in the nail is rare [1], although it is the most common epithelial malignancy of the nail apparatus [1, 2]. Less than 300 cases of subungual SCC (invasive or in situ) have been reported in the English-language literature [2]. The clinical diagnosis of this type of tumor may be difficult and is often missed and/or delayed because of the heterogeneity o...