Nodules

CLINICAL DIAGNOSTIC MANUAL

Nodules are palpable, solid, circumscribed skin or subcutaneous lesions that generally measure more than 1 cm in diameter. They can develop anywhere on the body and vary in consistency, mobility, and tenderness to touch. Nodules may be benign or malignant, and their etiology can be inflammatory, infectious, neoplastic, or degenerative. Identifying and evaluating nodules is essential to determine their origin and plan appropriate management.

Pathology	Symptoms and Clinical Signs	Suspected Diagnosis	Confirmatory Diagnosis
Sebaceous cyst	Subcutaneous, soft, mobile nodule, often with a central punctum. Usually asymptomatic.	Medical history and physical examination. Soft tissue ultrasound.	Confirmation with physical examination and ultrasound.
Lipoma	Subcutaneous, soft, mobile, asymptomatic nodule. Common on the trunk and limbs.	Medical history and physical examination. Soft tissue ultrasound.	Confirmation with physical examination and ultrasound.
Basal cell carcinoma	Pearly nodule with superficial telangiectasias. Common in sun-exposed areas.	Medical history and physical examination. Dermatoscopy.	Confirmation with skin biopsy and histopathological analysis.
Warts	Keratotic nodules, usually on hands and feet. Can be painful.	Medical history and physical examination. Dermatoscopy.	Confirmation with physical examination and dermatoscopy.
Xanthoma	Yellowish nodules. Associated with dyslipidemias.	Medical history and physical examination. Lipid profile.	Confirmation with lipid analysis and physical examination.
Acne	Inflammatory, painful nodules. Common on the face, chest, and back.	Medical history and physical examination. Dermatoscopy.	Confirmation with physical examination and dermatoscopy.
Dermatofibroma	Firm, usually brown nodule. Common on the extremities.	Medical history and physical examination. Dermatoscopy.	Confirmation with physical examination and dermatoscopy.
Squamous cell carcinoma	Firm, sometimes ulcerated nodule. Common in sun-exposed areas.	Medical history and physical examination. Dermatoscopy.	Confirmation with skin biopsy and histopathological analysis.
Keratoacanthoma	Rapidly growing nodule with a crateriform centre. Common in sun-exposed areas.	Medical history and physical examination. Dermatoscopy.	Confirmation with skin biopsy and histopathological analysis.
Gouty tophus	Firm nodules, usually on joints. Associated with hyperuricemia and gout.	Medical history and physical examination. Serum uric acid analysis.	Confirmation with uric acid analysis and physical examination.
Chondrodermatitis nodularis helicis	Painful nodule on the ear. Associated with constant pressure.	Medical history and physical examination. Dermatoscopy.	Confirmation with physical examination and dermatoscopy.
Rheumatoid nodules	Firm, non-painful nodules. Associated with rheumatoid arthritis.	Medical history and physical examination. Rheumatoid factor and anti-CCP analysis.	Confirmation with rheumatoid factor and anti-CCP analysis.
Heberden’s nodes	Hard nodules on the distal finger joints. Associated with osteoarthritis.	Medical history and physical examination. Hand X-ray.	Confirmation with hand X-ray.
Pyogenic granuloma	Vascular, bleeding nodule that grows rapidly. Common on extremities.	Medical history and physical examination. Dermatoscopy.	Confirmation with skin biopsy and histopathological analysis.
Malignant melanoma	Pigmented, asymmetric nodule with irregular borders. History of lesion changes.	Medical history and physical examination. Dermatoscopy.	Confirmation with skin biopsy and histopathological analysis.
Erythema nodosum	Painful nodules, usually on the legs. Associated with infections or systemic diseases.	Medical history and physical examination. Blood tests and chest X-ray.	Confirmation with blood tests and chest X-ray.
Polyarteritis nodosa	Painful nodules. Associated with systemic vasculitis.	Medical history and physical examination. Skin biopsy.	Confirmation with skin biopsy and histopathological analysis.
Lepromatous leprosy	Multiple nodules. Associated with chronic Mycobacterium leprae infection.	Medical history and physical examination. Skin biopsy and Ziehl-Neelsen staining.	Confirmation with skin biopsy and Ziehl-Neelsen staining.
Secondary syphilis	Nodules associated with systemic dissemination of Treponema pallidum. Skin and mucosal rashes.	Medical history and physical examination. Serological tests for syphilis.	Confirmation with serological tests (VDRL, RPR, FTA-ABS).
Lupus vulgaris	Chronic nodules. Associated with cutaneous tuberculosis.	Medical history and physical examination. Skin biopsy and tuberculin tests.	Confirmation with skin biopsy and positive tuberculin tests.
Swimming pool granuloma	Nodules in areas exposed to water. Caused by Mycobacterium marinum.	Medical history and physical examination. Skin biopsy culture.	Confirmation with skin biopsy culture positive for Mycobacterium marinum.