A case of hypermelanosis in a phylloid pattern

Phylloid terminal hair nevus: A unique clinical entity

We present a case of an otherwise healthy infant with a localized patch of phylloid hypopigmentation bordered by terminal hairs on the back. We believe that this is a unique clinical entity and propose the term "phylloid terminal hair nevus." We believe that this is a localized form of phylloid hypomelanosis that is not associated with extracutaneous abnormalities.

Phylloid hypermelanosis: a cutaneous marker of several different disorders?

Phylloid hypermelanosis is a less clearly defined pigmentary disturbance than its hypopigmented counterpart, phylloid hypomelanosis. We report the case of a 32-month-old boy who had multiple melanotic macules arranged in a typical phylloid pattern since birth. He also had an abnormal facial appearance, with macrocephaly, frontal bossing, hypertelorism, internal strabismus, and auricular deformities. Psychomotor delay, multiple cystic brain lesions, and bilateral sensorineural hearing loss were also found. A review of associated anomalies as described in this and five previously reported patients with phylloid hypermelanosis shows some vague and inconsistent similarities, such as unusual facial appearance, malformed ears, hearing loss, and mental deficiency, but it is likely that phylloid hypermelanosis represents a class of heterogeneous phenotypes. Future clinical and genetic research may show how many distinct entities can be placed in this group of disorders.

Pigmentary mosaicism and specific forms of phylloid hypo- and hypermelanosis

Pigmentary mosaicism is proposed to encompass all pigment anomalies caused by chromosomal mosaicism. The concept includes, not only pigment anomalies following the lines of Blaschko, but also pigmentary disorders with phylloid, checkerboard and patchy pigmentation without midline separation. The representative disorders are hypomelanosis of Ito (pigmentary mosaicism of hypopigmented or Ito type), linear and whorled nevoid hypermelanosis (pigmentary mosaicism of hyperpigmented type), pigmentary mosaicism of hypopigmented and hyperpigmented type, and phylloid hypo- and hypermelanosis. Pigmentary mosaicism is nowadays recognized as a pigmentary disorder caused by somatic chromosomal abnormalities disrupting or accelerating the function of pigmentary genes. Affected individuals with pigmentary mosaicism commonly have multiple congenital abnormalities, developmental delays and/or mental retardation. However, the complication is not a syndrome because functional loss or acquisition due to various chromosomal abnormalities induces pigment abnormalities and specific complications. Cytogenetic abnormalities, including polyploidy, aneuploidy, deletions, insertions and translocations, are associated with almost any chromosome and tissue-limited mosaicism for chromosome abnormalities. Cytogenetic findings in cases with the phylloid pattern demonstrate the obvious causal relationship between phylloid hypomelanosis and mosaic trisomy 13. The pattern of cutaneous mosaicism depends on the trajectory of migration and proliferation during embryogenesis. The chromosomal regions of hot breakpoints in pigmentary mosaicism may contain pigmentation-associated genes. The accumulation of relationships between cases and chromosomal analyses may provide the opportunity to identify and understand the pigmentation-associated genes because more than 800 phenotypic alleles are known in the mice models of pigmentary anomalies and not all color loci have been identified. Here, we summarize the clinical features of pigmentary mosaicism and specific forms of phylloid hypo- and hypermelanosis.