Cutaneous Basal Cell Carcinoma

Nayela Keen, MD

Christine M. Glastonbury, MBBS

Key Facts

Terminology

Cutaneous tumor, the cells of which resemble basal cells of epidermis
Most common skin cancer
- 75% of all nonmelanoma skin cancer in USA
90% in sun-exposed head and neck region

Imaging

Most lesions superficial and not imaged
Ulcerative lesion with heaped-up tumor margins
MR generally preferred for superior definition of tumor infiltration and perineural spread
Noncontrast CT if concern for bony invasion

Top Differential Diagnoses

Cutaneous SCCa
Cutaneous melanoma
Merkel cell carcinoma

Pathology

Ultraviolet radiation-induced skin tumor
Other predisposing factors: Immunosuppression, ionizing radiation, arsenic, burn scars, genetic syndromes

Clinical Issues

Slow growing, tends to invade local tissues
Nodal or distant metastases rare
Treated primarily by complete resection

Diagnostic Checklist

MR best if invasive disease suspected
Imaging often underestimates extent of tumor
Look for extension into deep structures and surrounding tissues
Look for perineural spread along cranial nerves 5 & 7

(Left) Clinical photograph shows patient who had been lost to follow-up for 8 years following excision of right ear BCCa. Large ulcerative lesion

completely erodes right auricle and extends into cheek, exposing underlying temporal bone. (Right) Axial bone CT in same patient shows extensive abnormality of squamous and petrous temporal bone with both permeative change

and gross destruction

. Middle ear is opacified with tumor, which is also partially eroding and displacing ossicles

(Left) Axial T2WI MR in same patient demonstrates predominantly infiltrative lesion

mildly hyperintense as compared to muscle. Tumor erodes the thickness of facial soft tissues, including muscles and right parotid gland. (Right) Axial T1WI C+ MR at a slightly higher level reveals only mild enhancement of infiltrating margins of tumor

as temporal bone and facial tissues are eroded. Note dural enhancement and thickening

, indicating intracranial extension.

TERMINOLOGY

Abbreviations

Basal cell carcinoma (BCCa)

Synonyms

Also referred to as a “rodent ulcer”

Definitions

Cutaneous slow growing tumor, the cells of which resemble basal cells of epidermis (outer skin layer)
- Tendency for local tissue invasion; metastases rare

IMAGING

General Features