Etched as a Tear Track, Bifurcated at Right Angles: The Patterned Spectrum of Facial Linear Porokeratosis

A 24-year-old woman presented with facial lesions persisting for 4 years. Clinical examination revealed annular plaques with raised, hyperkeratotic edges and central atrophic areas. The plaques were arranged in distinct linear patterns, all following Blaschko’s lines. One linear plaque extended from the left medial canthus along the nasolabial fold and another from the medial end of the left eyebrow to the nasal bridge [Figure 1a]. Three others radiated from a single point along the right mandibular margin [Figure 1b]. Dermoscopy showed a well-defined hyperpigmented ‘double-edged rim’ studded with blue-grey dots [Figure 2a]. Histopathology confirmed porokeratosis through a cornoid lamella [Figure 2b].

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Figure 1:

(a) Discrete annular plaques on the right eyelid along with two linear plaques, one extending from medial canthus along nasolabial fold, showing a tear track-like pattern, while the other extending from medial end of eyebrows up to the middle of nasal bridge on the left side of the face. (b) Three linear plaques all arising from a single point on the right mandibular margin, radiating outward in a distinctive right-angled, bifurcated pattern.

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Figure 2:

(a) Polarised dermoscopy image (DermLite DL4) showing hyperpigmented double-edged rim (red arrow) with multiple brown to black dots and central skin coloured to hyperpigmented area consisting of brownish and white dots at few places (blue star 10 x). (b) Section shows skin with epidermis showing a coronoid lamella (black arrow). The dermis shows mild perivascular lymphocytic infiltrate. Haematoxylin and Eosin, ×100.

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Broad-spectrum sunscreen and topical 5% 5-fluorouracil were initiated. Patient is planned for regular follow-up to monitor progression and malignancy risk. Previous reports of linear porokeratosis have described atypical presentations, including facial involvement along Blaschko’s lines or lesions on the palms and proximal extremities.^[1-3] Our case exhibits a unique tear track and right-angled bifurcation configuration on the face, thereby expanding the recognised morphological spectrum of linear porokeratosis.