Segmental hypomelanosis and hypermelanosis arranged in a checkerboard pattern are distinct naevi: flag‐like hypomelanotic naevus and flag‐like hypermelanotic naevus

Abstract

The categorization of congenital hypo- or hyperpigmented skin lesions following a segmental pattern has been a long-lasting matter of debate and have been reported under various and often incorrect terms. To reassess published hypomelanotic and hypermelanotic lesions that did not follow Blaschko lines nor a phylloid pattern of mosaicism, we carried out an extensive and critical review of the worldwide literature. Seventy-four retrieved cases consisted of lateralized hypomelanotic lesions arranged in a flag-like pattern or appearing as large patches of grossly oval or angulated shape and sharp, serrated margins. Sometimes lesions harboured maculopapular melanocytic naevi or cooccurred with other segmentally arranged naevi. A probably non-random association with extracutaneous anomalies was also reported on rare occasions. In 70 cases, lateralized hypermelanotic patches were arranged in a flag-like pattern that often appeared as large quadrangular patches. Sometimes lesions harboured Spitz naevi. Ten cases belonged to phacomatosis melanorosea, whereas several others were part of so far uncategorized cases of phacomatosis pigmentovascularis. Flag-like hypomelanosis is a distinct naevus type, for which the term 'flag-like hypomelanotic naevus' is suggested. Its cooccurrence with extracutaneous abnormalities might represent a specific syndrome. Flag-like hypermelanosis is a distinct naevus type, for which the term 'flag-like hypermelanotic naevus' is suggested. Its co-occurrence with naevus roseus defines phacomatosis melanorosea. Flag-like hypermelanotic naevus should be distinguished from the checkerboard-like areas of darker skin as observed in chimaeras.

A Rare Case of Checkerboard-Like Becker Nevi with a Unique Distribution of Abnormalities

“…As a result, checkerboard skin pattern, which consists of multiple skin lesions, is sometimes reported to co-occur with extracutaneous abnormalities with frequent topographic correspondence between the skin lesions and the tissues involved. It is occasionally found in a number of different genetically determined syndromes [6]. Though multiple Becker nevi in one patient can be found from time to time, only few exhibit the real checkerboard configuration, emphasizing that checkerboard-like skin pattern is considered a rare condition among cases of Becker nevi or Becker nevus syndrome.…”

Phacomatosis melanocesioflammea: the rediscovery of phacomatosis pigmentovascularis type IV

“…Phacomatosis pigmentovascularis (PPV) is a term encompassing several clinicogenetic entities defined by the coexistence of a segmental pigmented nevus of melanocytic origin and systematized capillary nevus. There are four well‐established types of PPV, that is, phacomatosis cesioflammea (by far the most commonly reported), phacomatosis cesiomarmorata, phacomatosis spilorosea, and phacomatosis melanorosea 1,2 . All cases not fitting such diagnoses have been variously labeled as either “unclassifiable PPV” or assigned a novel, descriptive name 1,2 .…”

“…There are four well‐established types of PPV, that is, phacomatosis cesioflammea (by far the most commonly reported), phacomatosis cesiomarmorata, phacomatosis spilorosea, and phacomatosis melanorosea 1,2 . All cases not fitting such diagnoses have been variously labeled as either “unclassifiable PPV” or assigned a novel, descriptive name 1,2 . Following up on a recent article calling for the recognition of “phacomatosis cesio‐flammeo‐marmorata” as an additional PPV type, 3 I would like to bring to attention a cluster of previously reported cases that might constitute yet another PPV variant.…”

Archetypical Patterns of Skin Manifestations in Neurocutaneous Disorders

“…63,64 New entities belonging to this group are the "flag-like hypomelanotic nevus" and "flag-like hypermelanotic nevus" (i.e., the old entities categorized as "segmental hypomelanosis or hypermelanosis arranged in a checkerboard pattern"). 65 Their co-occurrence with extracutaneous abnormalities might represent specific syndromes. 65 Phylloid Pattern (Type 3 Archetypical Pattern)…”

“…65 Their co-occurrence with extracutaneous abnormalities might represent specific syndromes. 65 Phylloid Pattern (Type 3 Archetypical Pattern)…”