A Sporadic Case of Ichthyosis Curth Macklin: Rare Presentation of a Rare Disease.

Ichthyosis hystrix is a rare autosomal dominant genodermatosis, characterized by persistent spiny hyperkeratotic scales which cover a significant part of the skin surface. Based on the pattern of distribution, five clinical variants namely Brocq type, Lambert type, Curth-Macklin type, Rheydt type and Bδfverstedt type have been described. We report the case of an 11-year-old male child with spiny, hyperkeratotic scales all over the body since birth with sparing of scalp and central part of the face. Palmoplantar keratoderma was also present. These clinical features are suggestive of Ichthyosis Curth Macklin, which has been typically described in families. However, family history was negative in our patient. The case is being reported on account of rarity of the disease, that too with a very rare sporadic presentation.

What was known?

Curth-Macklin variant of ichthyosis hystrix is a rare autosomal dominant genodermatosis. It has been, reported in two families and very few sporadic cases till date to the best of our knowledge.

Introduction

Ichthyosis hystrix (IH) is a rare genodermatosis. It usually presents at, or soon after birth with hyperkeratotic verrucous dark-brown ridges. ‘Porcupine men’ and ‘systematized epidermal naevus’ have also been used to describe these lesions. Based on the pattern of distribution, five clinical variants namely Brocq type, Lambert type, Curth-Macklin type, Rheydt type and Bäfverstedt type have been described. We report a case of Curth-Macklin variant of ichthyosis hystrix with the absence of family history. It has been described to run in families as an autosomal dominant trait, very few sporadic cases of the entity have been described in the literature. The extreme rarity of the condition prompted us to report the case.

Case Report

An 11-year-old male child presented with asymptomatic, dark-brown, spiny, hyperkeratotic, verrucous scales and ridges all over body since birth. The patient gave history that scales shed after scrubbing and reappear in 5-7 days. The patient was born of a full-term, normal vaginal delivery. There was no history of parental consanguinity, collodion presentation at birth, blistering or erythroderma. None of the family members were affected.

On examination, the affected skin showed symmetrically distributed, generalized, thickened, verrucous, dark-brown cobblestone-like lesions [Figure 1a]. There was sparing of scalp and central part of face with involvement of ear [Figure 1b]. Axillary region, dorsum of hand, popliteal fossa and antecubital fossa were less markedly affected [Figures 1a and 2a]. Severe palmoplantar keratoderma and fissuring was seen [Figure 2b]. Hair, nails, teeth, mucosa and other systemic examination was normal.

Figure 1

(a) Generalized dark-brown, spiny, hyperkeratotic, verrucous scales and ridges. (b) Involvement of ear with sparing of central part of face

Figure 2

(a) Spiny scales with relative sparing of dorsum of hand. Nails are normal (b) Keratoderma and fissuring of sole

Skin biopsy (H and E staining) showed hyperkeratosis, acanthosis and papillomatosis with thick granular layer [Figure 3a]. Perinuclear vacuolization and coarse keratohyaline granules were seen in upper spinous layers [Figure 3b]. Electron microscopy could not be performed due to lack of facilities.

Figure 3

(a) H and E staining, ×40 showing hyperkeratosis, acanthosis and papillomatosis with thick granular layer (b) H and E staining, ×100 showing hyperkeratosis with perinuclear vacuolization and coarse keratohyaline granules seen in an upper spinous layer

Discussion

Ichthyosis hystrix is a poorly defined entity which encompasses disorders displaying striking hyperkeratotic verrucous brown ridges. It is an extremely rare disorder, reported in only a few families and sporadic cases. Five clinical variants have been described: Brocq type, Lambert type, Curth-Macklin type, Rheydt type and Bäfverstedt type.[1] The distinctive distribution of lesions, associated abnormalities and inheritance patterns help to differentiate between these forms.

In Brocq type, erythroderma and blistering is characteristic, and nevoid forms are less common.[2] Rheydt type shows hyperkeratosis over face and limbs along with hearing loss.[2] Bäfverstedt type was described in a single case which had striking follicular hyperkeratosis and mildly affected palms.[2] Lambert type, seen in the Lambert family with 11 affected members across four generations, has no blistering with sparing of face, palms and soles.[2]

Curth-Macklin type is an autosomal dominant variant of ichthyosis hystrix. Two large families[13] with autosomal dominant inheritance and very few sporadic cases[456] have been reported since its first description in 1954. It results from heterozygous frameshift mutation in keratin 1 gene (KRT1), and a new mutation for this disease has recently been reported.[7] Recently, it has been suggested to rename the entity as Ichthyosis Curth-Macklin and group it under keratinopathic ichthyoses, along with epidermolytic ichthyosis and superficial epidermolytic ichthyosis.[8] There is wide variability in its time of onset and clinical presentation,[456] which varies even within families.[123] It is characterized by massive palmo-plantar keratoderma leading to deep, bleeding, and painful fissures.[8] There is development of hyperkeratotic, ridged or cobblestoned plaques over the large joints and/or hyperkeratotic papules on trunk and extremities. The verrucous plaques are often symmetrically widespread and involve nearly the entire body. There is no skin fragility or scalp abnormality.[8] Histopathological features include hyperkeratosis, acanthosis, and papillomatosis, along with the characteristic findings of perinuclear vacuolization and binucleate keratinocytes.

The clinical and histopathologic findings in our patient were consistent with those of Ichthyosis Curth-Macklin. This can be further confirmed by electron microscopy which also reveals keratin intermediate filaments aggregated into continuous, peripheral shells, without keratin clumping typical for epidermolytic hyperkeratosis.[9] The same could not be performed in our patient due to lack of such facilities. Epidermolytic hyperkeratosis was the closest differential diagnosis in our case. However, it was ruled out by absence of history of blistering at birth and presence of very thick palmoplantar hyperkeratotic scales.

Our case, with severe palmoplantar keratoderma, generalized involvement with relative sparing of face and scalp, along with absence of blistering, erythroderma and deafness, and no family history of ichthyosiform disease, are suggestive of sporadic type of Ichthyosis Curth-Macklin which is a very rare entity.

What is new?

The patient is a sporadic case of Curth-Macklin variant of ichthyosis hystrix. It is being reported on account of its extreme rarity.