Nodule: a firm, elevated, circumscribed, easily palpable and indurate lesion, usually with sharp borders, that is thicker or deeper than the average papule and > 1 cm or plaque; it can involve all skin layers.
More extensive increase in substance of skin.
Colors: skin-colored, brown, red, yellow.
May appear anywhere on body; can be solitary, localized or disseminated.
May progress to necrosis, ulcer or scar.
Comment / Explanation
Distinction between papule and nodule is by size.
Larger nodule = tumor (benign or malignant cell proliferation).
Tumor: nodular basal cell carcinoma, nodular melanoma.
Infection: furuncle, abscess.
Inflammatory disease: prurigo, erythema nodosum, sarcoidosis.
Benign and malignant cell proliferations (granuloma, tumor).
Inflammation (furuncle, abscess).