Congenital Systematized Basaloid Follicular Hamartoma with Microphthalmia and Hemimegalencephaly

Abstract

The lines of Blaschko are a cutaneous pattern of mosaicism present in a variety of skin disorders. Developmental abnormalities affecting other tissues derived from the embryonic ectoderm and mesoderm are sometimes associated. Here, we describe a 5-year-old boy with basaloid follicular hamartoma affecting the left side of the body in linear multiple bands, following Blaschko lines. Lesions were predominantly hypopigmented macules and streaks, but among these, we could observe brownish atrophic patches and brown papules. Furthermore, ipsilateral hemimegaloencephaly and microphthalmia were present. These findings suggest a neurocutaneous condition recently described by Happle and Tinschert. Its nosologic classification will be discussed.

Molecular evidence of type 2 mosaicism in Gorlin syndrome

“…[9][10][11][12] Admittedly, the clinical and histopathological features of our patient show some overlap, but the following differences should be c.543_549delGGCACTC p.S181SfsX36 considered. [9][10][11][12] Admittedly, the clinical and histopathological features of our patient show some overlap, but the following differences should be c.543_549delGGCACTC p.S181SfsX36 considered.…”

“…For differential diagnosis one might consider Happle-Tinschert syndrome (HTS), which includes segmentally arranged basaloid follicular hamartomas (BFHs), linear atrophoderma, and osseous, dental or cerebral defects. [9][10][11][12] Admittedly, the clinical and histopathological features of our patient show some overlap, but the following differences should be considered. An odontogenic cyst as noted in the present case has so far not been reported in patients with HTS.…”

Happle-Tinschert Syndrome: Report of a Case with Hemimegalencephaly

“…However, despite this schema, the classification of hemimegalencephaly may be problematic due to overlapping of different grades (4). Before our case, Boccaletti et al (3) reported a case with a mild (grade 1) form of hemimegalencephaly. No apparent cortical anomaly was detected in their patient.…”

“…The main cutaneous finding of this disease is the presence of unilateral segmentally arranged basaloid follicular hamartomas. Associated abnormalities reported so far in Happle-Tinschert syndrome are skeletal findings (disproportionate overgrowth or deficient growth of limb bones, scoliosis, widening of ribs, rudimentary ribs, polidactyly, syndactyly, malformed thumb, socket-type or saddle nose, frontal bossing, abnormal bone mineralization, ipsilateral premature closure of epiphyses), dental pathologies (anodontia, hypodontia, enamel defects), cerebral anomalies (mental retardation, unsteady gait, enlarged ventricle, ipsilateral hemiplegia, mild hemimegalencephaly) and other disorders such as microphtalmia, coloboma of optic nerve, cataract or an imperforate anus (1, 2, 3). In addition, ipsilateral tumors appear to have an increased incidence; medulloblastoma, optic glioma, menengioma, ameloblastoma of the mandible and colonic adenocarcinoma have been reported in patients with Happle-Tinschert syndrome (1, 2, 3).…”

“…He described the disease as 'segmentally arranged basaloid follicular hamartomas, linear atrophoderma with hypo- and hyperpigmentation, enamel defects, ipsilateral hypertrichosis, and skeletal and cerebral anomalies' and proposed the name 'Happle-Tinschert syndrome'. Recently, a patient with microphtalmia and hemimegalencephaly was presented by Boccaletti et al (3) as the 11th case, all of which were reported in the dermatology literature.…”