Spitzoid melanoma is a rare variant of skin cancer, named for its microscopic similarity to a benign skin lesion called a Spitz nevus. This melanoma begins when melanocytes, the cells that produce skin color, grow uncontrollably to form tumors. It is identified more often in younger individuals than other types of melanoma and appears as a new or changing mole, often on the arms, legs, or face.
Understanding the Spitzoid Spectrum
The term “spitzoid” describes a spectrum of skin lesions ranging from harmless to malignant. On one end is the Spitz nevus, a benign mole common in children and adolescents. Although these growths can appear suddenly and grow rapidly, they are not cancerous. Their pink or reddish color and dome shape can be alarming.
In the middle are Atypical Spitz Tumors (ASTs). These lesions are a diagnostic gray area, with features that are not entirely benign but do not meet the full criteria for melanoma. They are also called Spitzoid Tumors of Uncertain Malignant Potential (STUMP), reflecting the difficulty in predicting their behavior. Few of these tumors progress to melanoma, but they warrant close observation or removal.
At the far end of the spectrum is spitzoid melanoma, the malignant lesion. This skin cancer can spread to other parts of the body if not treated. It is the cancerous counterpart to the benign Spitz nevus, and distinguishing between them is a diagnostic challenge. Spitzoid melanomas can be red, skin-colored, brown, or black.
Diagnostic Challenges and Procedures
Diagnosing a spitzoid lesion begins with a clinical examination. A dermatologist uses a dermatoscope, a handheld magnifying lens, for a detailed view of the lesion’s structure and color patterns. Since spitzoid melanomas often do not follow the “ABCDE” rules of melanoma, visual inspection alone is insufficient.
A definitive diagnosis requires a skin biopsy, where the lesion is surgically removed for analysis. An excisional biopsy, which removes the entire growth and a small margin of tissue, is the preferred method. This provides the pathologist with the complete lesion to assess its architecture and depth.
The core of diagnosis is histopathology, where a pathologist examines the biopsied tissue under a microscope. This step is a challenge because the cells of a Spitz nevus and a spitzoid melanoma can look very similar. Pathologists look for clues like asymmetry, poor circumscription, and cell division (mitotic figures) deep within the lesion to identify melanoma.
When microscopic examination is inconclusive, pathologists may use ancillary molecular or genetic tests to differentiate between benign and malignant lesions. Techniques like Fluorescence In Situ Hybridization (FISH) or Comparative Genomic Hybridization (CGH) can detect chromosomal abnormalities that are more common in melanomas.
Treatment Protocols for Spitzoid Melanoma
Once spitzoid melanoma is confirmed, the primary treatment is a wide local excision. The surgeon removes the tumor along with a margin of surrounding healthy skin to prevent the cancer from recurring at the original site. The size of the margin depends on the melanoma’s thickness.
A sentinel lymph node biopsy (SLNB) is often performed at the same time to determine if melanoma cells have spread to nearby lymph nodes. The surgeon removes the first lymph node(s) where cancer would likely spread for examination by a pathologist. The results of the SLNB help stage the cancer and guide further treatment.
If the SLNB reveals that melanoma has spread, or if the cancer is advanced, additional treatments are considered. These therapies include immunotherapy, which helps the body’s immune system fight cancer, or targeted therapy, which uses drugs that attack specific vulnerabilities in cancer cells.
Prognosis and Long-Term Management
The prognosis for spitzoid melanoma is influenced by several factors, primarily the tumor’s thickness and whether it has spread. The Breslow depth, the tumor’s thickness in millimeters, is a prognostic indicator. Thinner tumors confined to the skin have a more favorable outcome.
When detected and treated early, the outlook for spitzoid melanoma is positive and highly curable. The prognosis for children is often better than for adults. For example, one study found a five-year survival rate of 88% for children aged 10 and under whose spitzoid melanoma had spread.
Following treatment, long-term management involves regular follow-up appointments with a dermatologist for full-body skin examinations. These check-ups monitor the original site for any signs of recurrence.
Patients are also taught how to perform regular self-examinations of their skin. Monitoring for any new or changing moles is a part of ongoing care, as this surveillance helps in the early detection of any new primary melanomas.