Nodules are larger and deeper than papules. They are variable in shape and may have a mixture of epidermal, dermal, and subcutaneous components. Example A illustrates a large dermal infiltrate of neoplastic cells, as might be seen in a cutaneous T-cell lymphoma, or granulomatous inflammation, as might be seen in mycobacterial or deep fungal infection. Example B illustrates a dome-shaped nodule with a central crater filled with debris and a hyperplastic epidermis.
The large, egg-shaped, smooth, flesh-colored tumor behind this individual's ear has developed an ulcer and eschar on part of its surface. An important clue to the malignancy of this lesion is given by the prominent neovascular channels overlying the smooth surface of the tumor.
This tumor has destroyed part of the concha and all of the tragus. The tumor has a rolled border and a necrotic, ulcerated center. This constellation of findings is diagnostic for basal cell epithelioma, the most common malignant tumor arising in skin. This tumor has little potential for metastasis, but can be locally very destructive.
These shiny, tense, reddish-brown papules and nodules in the area of the axilla appear to arise at different depths in the skin. They are rather poorly circumscribed, suggesting that the major element of the pathological process occurs in the dermis. These lesions are not diagnostic, but strongly suggest neoplastic infiltrates such as those from malignant melanoma, lymphoma, leukemia, or Kaposi's sarcoma; or granulomatous inflammation, perhaps from tuberculosis, sarcoidosis, leprosy, or occupational exposure to beryllium, silica, or zirconium. This patient had metastatic malignant melanoma.
These tumors and nodules are flesh-colored and very indistinct, indicating that the major element of the pathological process occurs in the deep dermis or subcutaneous tissues. These symmetrical soft nodules and tumors represent thef most common benign neoplasms of adipose tissue, lipomas, which arise in, and are limited to, the subcutaneous fat.