FMGE 2018 — Dermatology

Q: Most common subtype of Rodent ulcer is:

Nodular. ***Nodular*** - The **nodular** subtype is the most common presentation of **basal cell carcinoma (rodent ulcer)**, accounting for 60-80% of cases. - It typically appears as a **pearly nodule** with rolled borders and telangiectasias. *Superficial* - The **superficial** subtype is the second most common, accounting for 15-20% of basal cell carcinomas. - It presents as a **red, scaly patch**, often mistaken for eczema or psoriasis. *Pigmented* - The **pigmented** subtype is less common, characterized by the presence of **melanin**, making it appear dark brown or black. - It can be confused with melanoma due to its dark coloration. *Cystic* - The **cystic** subtype is a rare form of basal cell carcinoma, characterized by a **fluid-filled lesion**. - It often appears as a translucent nodule with a soft, jelly-like consistency. [Practice more Dermatology PYQs on OnCourse]

Q: A child presents with the skin lesions shown in the image. The most likely diagnosis is:

Impetigo contagiosa. ***Impetigo contagiosa*** - The image shows **honey-colored crusted lesions** around the mouth, which are highly characteristic of **impetigo contagiosa (non-bullous impetigo)**. - This form of impetigo is typically caused by *Staphylococcus aureus* or *Streptococcus pyogenes* and primarily affects superficial layers of the epidermis. *Bullous impetigo* - Characterized by **flaccid bullae** (blisters) that rupture to leave a thin, varnish-like crust, rather than the thick honey-colored crusts seen here. - It is exclusively caused by **Staphylococcus aureus** strains producing exfoliative toxins. *Ritter disease* - Also known as **Staphylococcal Scalded Skin Syndrome (SSSS)**, this condition involves widespread **erythema and exfoliation** resembling a burn. - It is a severe, systemic illness with widespread skin involvement, not localized crusted lesions like those pictured. *Ecthyma* - This is a more **deep-seated skin infection** that penetrates into the dermis, characterized by **"punched-out" ulcers** with thick, adherent crusts and often leaves scars. - While also caused by *Staphylococcus aureus* and/or *Streptococcus pyogenes*, its lesions are typically more severe and destructive than what is depicted. [Practice more Dermatology PYQs on OnCourse]

2 Previous Year Questions with Answers & Explanations

Questions

Most common subtype of Rodent ulcer is:

A child presents with the skin lesions shown in the image. The most likely diagnosis is: