Pigmented Fibroepithelioma of Pinkus in Pregnancy: Strengths and Limitations of Reflectance Confocal Microscopy, Line‐Field Optical Coherence Tomography and Line‐Field Optical Coherence Tomography Artificial Intelligence Tool

Pigmented fibroepithelioma of Pinkus (FeP), a rare fibroepithelial variant of basal cell carcinoma (BCC), is clinically and dermoscopically challenging to diagnose and may mimic melanoma as well as benign lesions, such as sebhorreic keratosis. In pregnancy, a newly detected or progressively enlarging pigmented lesion raises additional diagnostic and management challenges, as timely and accurate classification must be balanced with maternal–foetal safety. A 31‐year‐old woman at 38 weeks' gestation presented with a slowly enlarging 5 × 7 mm translucent black–brown papule on the right abdominal flank. Dermoscopy showed a light‐brown structureless background with patchy blue blotches, peripheral linear irregular/serpentine vessels and a central milia‐like cyst/rosette under polarized light. Reflectance confocal microscopy (RCM) revealed, at higher magnification, epidermis‐derived anastomosing basaloid cords with peripheral palisading and occasional clefting, with abundant plump bright cells in the stroma consistent with melanophages; these features were compatible with pigmented FeP and explained a deceptive low‐magnification ‘ringed’ appearance. Line‐field optical coherence tomography (LC‐OCT) revealed epidermis‐originating anastomosing cords surrounding hyper‐reflective cell aggregates or hypo‐reflective stroma. The device's embedded LC‐OCT artificial intelligence classifier provided only focal ‘BCC‐consistent’ outputs while labelling other areas as melanocytic, underscoring the need for critical, whole‐lesion review. Given the third‐trimester status and low‐risk tumour behaviour, excision was deferred until postpartum. Histopathology confirmed pigmented FeP, with thin epithelial cords and strands arborizing in a collagenous stroma with ectatic vessels and superficial dermal melanin. Multimodal RCM and LC‐OCT assessment revealed therefore useful and consistent, resolving diagnostic uncertainty in pregnancy and enabling individualized timing of surgery. Pigmented FeP may lack canonical LC‐OCT patterns and may mislead low‐magnification RCM or AI outputs; therefore, high‐resolution assessment and cautious interpretation are essential.