In 1936, Curth1 reported a remarkable case of acanthosis nigricans (AN) with both unilateral linear and symmetrical nonlinear changes. Herein, arguments are presented for the concept that early loss of heterozygosity (LOH) caused the segmental skin lesions in this case, which were superimposed on less pronounced nonsegmental AN.
A 15-year-old boy presented with symmetrical lesions of AN “with exception of the strictly unilateral manifestation on the right side of the abdomen and the right groin”1 that had been present since birth (Figure 1). None of his family members was affected with AN. Bilateral, nonsegmental AN involving wide areas of the patient's body appeared when he was 10 years old (Figure 2). In 1959, Curth2 stated that “these symmetric changes completely subsided after puberty,” whereas “a large acanthotiform nevus, strictly confined to the right side of the abdomen, has been present since birth and has not undergone any changes at any period of his life.”
Happle R. Type 2 Segmental Acanthosis Nigricans: A Historical Case Explained by a New Concept. Arch Dermatol. 2008;144(12):1637. doi:10.1001/archderm.144.12.1637