Isolated plantar collagenoma

Molecular heterogeneity of the cerebriform connective tissue nevus in mosaic overgrowth syndromes

The clinical diagnostic criteria for Proteus syndrome were defined before the discovery of the AKT1 c.49G>A; p.(Glu17Lys) causal variant and used a combination of general and specific phenotypic attributes that could be combined to make a clinical diagnosis. The most heavily weighted specific criterion was the cerebriform connective tissue nevus (CCTN). Here, we describe two individuals with connective tissue nevi (CTNs) and some general attributes of Proteus syndrome who were found to have mosaic PIK3CA variants. CTNs on the soles of individuals with PIK3CA-related overgrowth typically exhibit thickening of the soft tissues with at most a wrinkled surface, but these two patients had firm plaques with ridges and furrows characteristic of CCTNs, which was histologically confirmed in one. These data show that CCTNs are not specific to Proteus syndrome and that clinicians should be cautious in diagnosing individuals with Proteus syndrome based on the CCTN alone. Rather, a complete evaluation should include careful assessment of other attributes of the diagnostic criteria and, whenever possible, genetic analysis of affected tissue.

Correction: Isolated collagenoma on the face: a rare occurrence

In the original printed version of the case report (1), the order of authors within the author list was incorrect. Shruti S was incorrectly listed as the second author and should have been listed as the first author. The PDF has been corrected accordingly and can be accessed at http://dx.doi.org/10.15570/actaapa.2019.9.

A limited form of proteus syndrome with bilateral plantar cerebriform collagenomas and varicose veins secondary to a mosaic AKT1 mutation

IMPORTANCE

Proteus syndrome is an extremely rare disorder of mosaic postnatal overgrowth affecting multiple tissues including bone, soft tissue, and skin. It typically manifests in early childhood with asymmetric and progressive skeletal overgrowth that leads to severe distortion of the skeleton and disability. The genetic basis has recently been identified as a somatic activating mutation in the AKT1 gene, which encodes an enzyme mediating cell proliferation and apoptosis.

OBSERVATIONS

We present a 33-year-old man who developed plantar cerebriform collagenomas on the soles of both feet and varicose veins in early childhood, in the absence of any skeletal or other connective tissue abnormality. Although the patient did not meet the diagnostic criteria for Proteus syndrome, he was found to have the c.49G>A, p.Glu17Lys AKT1 mutation in lesional skin but not in his blood.

CONCLUSIONS AND RELEVANCE

To our knowledge, this is the mildest molecularly confirmed case of Proteus syndrome, occurring in the absence of the characteristic skeletal overgrowth. These findings extend the spectrum of Proteus syndrome pathological characteristics and suggest that somatic mutations late in development and restricted in distribution cause subtle clinical presentations that do not meet the published clinical criteria.

Connective tissue nevi in children: institutional experience and review

BACKGROUND

Connective tissue nevi (CTN) are circumscribed hamartomas of the skin in which there is an abnormal mixture of normal components of the dermis that may be sporadic or associated with syndromes such as Buschke-Ollendorff, tuberous sclerosis, and Proteus.

OBJECTIVE

We sought to specify the clinical and histologic features of CTN in childhood and to propose a diagnostic approach and updated classification.

METHODS

This was a retrospective study in a tertiary pediatric outpatient population, accessing clinical and histopathological records.

RESULTS

We classified 114 cases of CTN from 1980 to 2008.

LIMITATIONS

The majority of cases were confirmed by histopathological examination. Therefore, our series excludes many CTN that were not biopsied. In addition, follow-up was variable.

CONCLUSION

Our series demonstrates the usefulness of a modified classification for CTN. Biopsy should be done when clinical diagnosis is uncertain, or in multiple lesions. When biopsy is performed it should include normal-appearing skin for comparison and, in Buschke-Ollendorff syndrome, limited anterior-posterior x-rays of the hands, wrists, feet, ankles, knees, and pelvis instead of a full skeletal survey.

Phacomatosis pigmentokeratotica: a follow-up report documenting additional cutaneous and extracutaneous anomalies

This is a follow-up report on a boy with phacomatosis pigmentokeratotica. At the age of 10 years he had, in addition to a sebaceous nevus and a speckled lentiginous nevus, multiple lesions of a collagen nevus localized on the chin and in the lumbar area. On the left shoulder, a small telangiectatic spot was present within the area of the speckled lentiginous nevus. Moreover, hemiatrophy of the left-hand side of the body and hyperhidrosis of the left lumbar area were noted. At the age of 16, the lesions of his collagen nevus had considerably enlarged and showed an arrangement along Blaschko lines. Additional pinhead-sized vascular lesions were noted, with preponderance within the area of the speckled lentiginous nevus in the left scapular region and on his left leg. Moreover, the boy had developed severe arterial hypertension since the age of 13. Angiographic examination showed an aortic stenosis that reached from the aortic arch down to the origin of the renal arteries, necessitating a surgical intervention. From this follow-up report we conclude that phacomatosis pigmentokeratotica may be associated with other cutaneous abnormalities such as linear connective tissue nevus of the collagen type and multiple pinhead-sized angioma-like lesions superimposed on the speckled lentiginous nevus. The associated defects of the large vessels may belong to the component of Schimmelpenning syndrome representing one "half" of phacomatosis pigmentokeratotica, rather than being part of the speckled lentiginous syndrome that forms the other "half" of this twin-spot phenotype.