Michelin Tire Baby Syndrome with Dermal Sclerosis: A Novel Association.

Sir,

Michelin tire baby syndrome (MTBS) is a rare autosomal-dominant genodermatosis. The name highlights its clinical resemblance to the mascot of a French tyre manufacturer.[1] It is a benign hamartomatous condition presenting as numerous ring-like circumferential thick skin folds (not lax), most commonly affecting the limbs.[2] The exact pathogenesis remains unclear, but diffuse lipomatosis seems to be the commonest pathology with rare instances of a smooth muscle hamartoma or abnormality of elastic fiber.[12]

A 9-month-old girl was referred to us from the Department of Pediatrics with asymptomatic, congenital skin folds affecting the distal parts of upper and lower extremities, progressively increasing with age. The child was born out of nonconsanguineous parentage, at term by normal vaginal delivery. The birth weight was 2.7 kg and her growth and developmental milestones were delayed for age. Family history was unremarkable.

She had a characteristic round face with bulged forehead, depressed nasal bridge, hypertelorism, thin upper lip, and short neck [Figure 1]. Cutaneous examination revealed multiple, symmetric, deep, gyrate skin creases affecting all four extremities along with buttocks and neck [Figures 2], without any truncal involvement. Hair, nail, and mucosae were spared. On further examination, we detected convergent squint [Figure 1], hypotonia, and hyperextensible joints. There was no restriction of neck or limb movements. There was no history of seizure corroborated by a normal MRI of brain. So, we made a diagnosis of MTBS, based on clinical features.

Figure 1

Characteristic round face with bulged forehead, depressed nasal bridge, hypertelorism, thin upper lip, and convergent squint (right eye)

Figure 2

Multiple, symmetric, deep, gyrate skin creases affecting all four extremities

Histopathological examination (HPE) demonstrated an unremarkable epidermis along with thickened and hyalinized dermal collagen bundles arranged haphazardly. Scattered periappendageal lymphocytic infiltrate was noticed in the dermis. The adnexal structures were atrophic and entrapped in the collagen along with diminished periadnexal and subcutaneous fat [Figures 3 and 4].

Figure 3

Normal epidermis with thickened, hyalinized collagen bundles and mild periappendageal lymphocytic infiltrate in the dermis (H and E, ×100)

Figure 4

Thick hyalinized collagen bundles arranged haphazardly in the dermis (H and E, ×400)

The parents were counseled regarding the prognosis of this condition and regular follow-up was advised.

MTBS is a rare genodermatosis characterized by excessive circumferential skin folds primarily affecting the extremities. This condition may be inherited autosomal dominantly, thus affecting successive generations of a family.[3] Bass et al. reported MTBS in seven individuals of four generations with three cases of male-to-male inheritance.[4] Reported chromosomal anomalies include deletion of the short arm of chromosome 11 and paracentric inversion of the long arm of chromosome 7.[5] We have reported a female child without any family history. Unfortunately, karyotyping could not be done because of limited resources. Other cutaneous complaints may include pruritus and hypertrichosis, but they were absent in our case.[13]

MTBS may occur as an isolated cutaneous finding or in association with other craniofacial abnormalities and systemic features. Facial dysmorphism like bilateral epicanthic folds, hypertelorism, squint, low set ears, cleft palate, and lips with hypoplastic teeth and mandible have been reported.[126] Uncommon anomalies include left-sided hemihypertrophy, hemiplegia and microcephaly, hypoplastic scrotum, inguinal or umbilical hernia, developmental delay, seizures, joint hypermobility, and congenital heart disease.[123] We noted hypertelorism, convergent squint, hypotonia, and hyperextensible joints in our patient. She also showed delayed development of milestones without any systemic abnormality.

MTBS may be associated with certain syndromes like Beare–Stevenson cutis gyrata syndrome, HITCH syndrome and MCA/MR syndrome. No such syndromic association was found in our patient.[1]

The exact pathogenesis of MTBS remains unclear. It is essentially a clinical diagnosis; HPE has been rarely performed. The commonest histological finding is deep dermal diffuse lipomatosis.[1] While smooth muscle hamartoma has been reported in few cases.[6] We observed dermal sclerosis in histopathology in our patient, and this histologic variation has not been reported till date.

Occasionally, circumferential skin folds may be a physiologic finding which needs to be differentiated from MTBS by the absence of craniofacial/systemic abnormalities and a normal skin biopsy.[2] If a single limb is involved, amniotic band sequence may be suspected (all features of MTBS are absent including genetic testing). Recently, Gupta et al. have reported a case of segmental infantile hemangioma mimicking MTBS.

The skin folds gradually diminish and disappear with age without any intervention.[6] Some remnant skin folds may exist till adulthood. Regular follow-up is advised to detect any systemic abnormality like seizures, mental retardation, and psychomotor delay. We have also advised the same for our patient.

To conclude, MTBS may be an isolated finding or associated with other syndromes and mental/developmental delay. Our patient also demonstrated several phenotypic abnormalities. Additionally, dermal sclerosis was noted on histology, which has not yet been reported till date. Thus, we have reported this case to generate awareness about this rarely reported condition and also to highlight a novel histologic finding.

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Conflicts of interest

There are no conflicts of interest.