A 5-month-old infant was referred to our hospital for a worsening bilateral groin rash, consisting of numerous brownish hyperkeratotic papules. According to his mother, he had had the rash since birth. Presumptive diagnoses were warts or condylomas. Skin biopsy showed massive epidermal hyperplasia with a markedly thickened stratum corneum (Fig. 1A). The corneocytes were flattened with increased eosinophilia, retention of nuclei, and numerous basophilic granules in the cytoplasm (Fig. 1B). Slight acanthosis was also observed. Periodic acid-Schiff staining was negative. No koilocytes were present. The biopsy specimen was dewaxed and then processed for electron microscopy. In the granular layer, small or large, round or stellate keratohyalin granules were present (Fig. 2A). In the stratum corneum, nuclei and numerous keratohyalin granules were still observed in the cytoplasm of the corneocytes (Fig. 2B). Persistence of intermediate filaments agglomerated in tonofilaments was observed. The cornified envelope was present. On the basis of these findings, we diagnosed congenital GP.
GP was initially known as “axillary GP” because the first cases were confined to this area. Since 1991, about 60 cases have been reported, all of which were in an intertriginous location.2 Only 9 cases in infants (aged from 3 to 24 months) have been reported, always confined to the napkin area.3,4 The lesions tended to be pruritic and present as hyperpigmented to bright red papules. In infants, GP has been already observed as bilateral linear plaques in the groins.5 The condition was easily diagnosed via a simple skin biopsy,2 showing a moderate regular hyperplasia with thickened stratum granulosum and corneum, containing nucleated corneocytes replete with basophilic granules, interspersed with areas of “agranular” parakeratosis and orthokeratosis. In our case, only GP was observed, and the aspect was comparable to that of previously reported cases. In 10 cases studied by electron microscopy,2 the majority of the corneocytes expressed keratohyalin granules and had a well-developed cornified envelope and elongated nuclei. Our findings were the same.
It is interesting to note that the diagnosis had once been reached through a simple examination of the rash scales.3
The etiology of the condition is uncertain and is believed to be caused by an acquired keratinization disorder. An excessive use of topical preparations (antiperspirants, creams, and perfumes, etc) has been reported. A defect in the conversion of profilaggrin into filaggrin, which leads to a failure to disperse keratohyalin granules and to aggregate keratin filaments during terminal epidermal differentiation has been suggested.2 Different treatments have been tried with varying degrees of success. Spontaneous resolution occurred in many cases. Although retinoids were expected to be effective, their results have been inconsistent.
To the best of our knowledge, our case is the first congenital case report of GP, and a rash induced by topical preparations is ruled out in our report. Unfortunately, we are unable to report on the outcome because our patient was lost to follow-up.
Stéphanie Leclerc-Mercier, MD*
Catherine Prost-Squarcioni, MD, PhD†‡
Dominique Hamel-Teillac, MD§
Sylvie Fraitag, MD*
*Department of Pathology, Necker-Enfants Malades Hospital, Paris Departments of †Histology; and ‡Dermatology, Avicenne Hospital, AP-HP, Bobigny, France §Department of Dermatology, Necker-Enfants Malades Hospital, Paris
1. Northcutt AD, Nelson DM, Tschen JT. Axillary granular parakeratosis. J Am Acad Dermatol
2. Metze D, Rütten A. Granular parakeratosis—a unique acquired disorder of keratinization. J Cutan Pathol
3. Patrizi A, Neri I, Misciali C et al. Granular parakeratosis: four paediatrics cases. Br J Dermatol
4. Pimentel DR, Michalany N, Morgado de Abreu MA, et al. Granular parakeratosis in children: case report and review of the literature. Pediatr Dermatol
© 2011 by Lippincott Williams & Wilkins.
5. Chang MW, Kaufmann JM, Orlow SJ, et al. Infantile granular parakeratosis: recognition of two clinical patterns. J Am Acad Dermatol