Grover's disease following multiple bilateral Blaschko lines: a rare clinical presentation with genetic and electron microscopic analyses.

Grover's disease is an acquired dermatosis of unknown cause histopathologically characterized by the presence of acantholysis. We report an 83-year-old Japanese man who showed multiple pruritic papular lesions distributed bilaterally along Blaschko lines, necessitating the exclusion of segmental Darier's disease. No mutations in ATP2A2, ATP2C1 or keratin 5 genes were found both in the lesional skin and in peripheral leukocytes, suggesting that putative pathogenesis of Grover's disease is distinct from those of other acantholytic dermatoses. Electron microscopy revealed poorly developed tonofibrils in the basal cells, and the structure of desmosomes appeared normal, with an increase in the number of desmosomes in the spinous layer, indicating compensation of defective desmosomal function. Impairment of desmosomal plaque proteins linking tonofilaments to desmosomal cadherins may thus account for acantholysis. The unusual bilateral mosaic arrangement in our patient may offer valuable clues to the genetic basis of Grover's disease.