CHAPTER 46 TUMORS, COMMON SKIN AND HAIR FOLLICLE 677
Some tumors (trichofolliculoma and dilated pore of Winer) have a central
depression or opening that contains keratin, hair, or sebaceous material (Fig-
ure 46.24)
Dilated pore of Winer may appear to form a cutaneous horn.DIFFERENTIAL DIAGNOSIS
Squamous cell carcinoma:
Draining abscesses or infected wounds
Claw bed infection/osteomyelitis
Other neoplasia (lymphoma, mast cell tumor)
Melanoma (may mimic Bowen’s disease)
Eosinophilic plaque.
Melanocytic tumors:
Amelanotic melanomas may look similar to undifferentiated sarcomas
Other neoplasms as well as infection.
Basal cell tumors:
Other neoplasms: mast cell tumors, melanoma, hemangioma, hemangiosarcoma
Epidermal or follicular cyst.
Sebaceous adenomas:
Other neoplasms
Cellulitis
Nevus
Apocrine adenomas, adenocarcinomas.
Hair follicle tumors: cysts, other neoplasms.
DIAGNOSTICS
Routine blood work: hemogram and serum chemistry.
Urinalysis.
Thoracic radiography: detects lung metastasis (3 view).
Abdominal radiography: evaluates and monitors sublumbar lymph nodes, if clinically
relevant (3 view).
Radiography of extremities: with digital tumor; determines extent of underlying bone
involvement.
Ultrasonography and CT/MRI may be helpful (especially tumors invading the ear
canal, oral cavity, sinonasal cavity).
Cytologic examination: fine-needle aspirate of the mass; evaluate regional and/or large
lymph nodes for metastasis.
Biopsy: needed to confirm diagnosis.
Histopathology
Squamous cell carcinoma: cords or irregular masses of dysplastic epidermal cells
infiltrating into the dermis and subcutis, keratin pearls (accumulations of compact