case_images: PMC11802424_01
case_images: Clinical presentation of the case. The patient presented with symmetric, focal palmoplantar keratoderma and obvious pseudoainhum on the weight-bearing areas of both feet (A,C). Palm region keratinous scale was observed in toe interdigital, desquamation and warmth in the extremities (B,D).
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case_images: fig1
case_images: A 31-year-old male presented to our outpatient clinic with symptoms including symmetrical focal PPK, intermittent episodes of warmth-induced pain and itching, sclerodactyly-like features, mild pseudoainhum, and skin peeling on the extremities (Figures 1A,B). He presented with mild keratosis and peeling, and thick yellow-brown, fissure hyperkeratic plaques on the pressure sites of the plantar (Figures 1C,D).
case_images: Clinical presentation of the patient's father. His father yellow showed thickened and dry hard, hypertrophic keratotic patches, clear erythema on both feet (A,B). Cone-shaped fingers and desquamation on the palms were observed on both hands (C,D).
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case_images: fig2
case_images: His father manifested with focal keratotic plaques, cone-shaped fingers, and desquamation on the palms (Figures 2A-D).
case_images: Histopathologic and ultrastructural features of the patient's skin lesion. Hematoxylin and eosin (H&E) staining of the skin lesion revealed psoriasiform hyperplasia characterized by dense hyperkeratosis (A), thickening of the skin layers (acanthosis), notable parakeratosis in the upper skin layers, reduced granular layer (hypogranulosis), and vesicular degeneration (B). Scale bar: A, x50; B, x100.
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case_images: fig3
case_images: The histopathologic findings of plantar skin lesion showed psoriasiform hyperplasia with compact hyperkeratosis, acanthosis, hypogranulosis, and parakeratosis of "corn-like" pattern in the stratum corneum with vesicular degeneration on the corneum and epidermis (Figures 3A,B).
case_images: Result of DNA sequencing of TRPV3 mutation in the patients' family. TRPV3 gene sequencing results revealed a identical heterozygous mutation c.1964 T > C (p.L655P) in this case and his father (A). The patient's mother and wife did not exhibit mutations at the same gene loci (B).
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case_images: fig4
case_images: TRPV3 sequencing results revealed an identical heterozygous mutation c.1964 T > C (p.L655P) in the patient and his father (Figure 4A). Additionally, the mutation was not detected in the patient's mother and wife (Figure 4B).
case_images: Treatment of this patient with erlotinib. Focal palmoplantar keratoderma and pseudoainhum were effectively relieved following therapy with erlotinib 75 mg for 3 months (A-C). Plantar surface of both feet showing mild erythema and subtle hyperkeratosis following therapy with erlotinib 75 mg for 5 months (D-F). Red triangle: Symptoms significantly improved.
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case_images: fig5
case_images: Within 3 months, significant improvement was noted, and subsequent examinations showed only mild redness and slight hyperkeratosis on both plantar surfaces after 5 months of treatment (Figure 5).