(BMJ)—A man in his 60s developed multiple brown plaques on his chest and back over the course of 6 months. He was otherwise asymptomatic. Exam: >500 verrucous brown lesions coalesced into plaques on trunk. What’s the dx?
Leser-Trélat sign
Squamous cell carcinoma
Warty dyskeratoma
Florid cutaneous papillomatosis
Cowden disease
You are correct. Rapid diffuse eruption of seborrheic keratoses is the hallmark of the Leser-Trélat sign, a paraneoplastic phenomenon associated with underlying malignancy (GI adenocarcinomas account for about half of cases). Although the precise pathogenesis remains unclear, it’s hypothesized that the development of seborrheic keratoses is stimulated by tumor-secreted growth factors and alterations to cytokines.

Further investigation in this patient revealed a moderately differentiated colorectal adenocarcinoma of the sigmoid colon. In patients with eruptive onset of large numbers of seborrheic keratoses in a short period, underlying malignancy should be considered.

BMJ 2021;374:n1966
(BMJ)—A boy presented with a 2-year hx of angular stomatitis and chapping of the lips that was refractory to topical steroid or emollient tx. Parents reported that the boy was a picky eater, and his growth was delayed (height and weight, <5th centile for age). Lips: fissures, red patches, oozing, yellowish crusts. Perianal skin: mild eczematous changes. What's the dx?
Atopic dermatitis
Biotin deficiency
Zinc deficiency
Candida infection
Impetigo
You are correct. Blood tests for suspected zinc deficiency showed plasma zinc levels of 10.27 μmol/L (normal: 13.77-18.36 μmol/L). After tx with zinc gluconate (78 mg/day) for 1 month, the chapping had resolved, and the boy subsequently gained height and weight.

Mild to moderate zinc deficiency affects at least one third of the global population. Although refractory cheilitis in children with delayed growth is a rare presentation, it warrants further investigation for zinc deficiency.

BMJ 2021;373:n1236