SAN DIEGO —
“For a pigmented Spitz nevus, we were taught to look for a starburst pattern, a central area of homogeneous pigment, and peripheral symmetrical streaks or pseudopods,” Dr. Piggott, an adult and pediatric dermatologist at Scripps Clinic, San Diego, said at the annual Cutaneous Malignancy Update. “For Spitz nevi without pigment, we were taught to look for symmetric dotted vessels.”
However, results from a retrospective study published in 2015 gave her pause in relying on dermoscopy alone for assessing Spitz nevi. Researchers from Italy, Japan, and Brazil studied excision specimens of 384 Spitzoid-looking lesions in patients 12 years and older. On histology, 86.7% were diagnosed as benign Spitz nevi and 13.3% were diagnosed as melanoma.
When the researchers looked at the dermoscopic images, many cases of atypical Spitz nevi were indistinguishable from the benign Spitz nevi. Now, Dr. Piggott said, “I respect the dermoscopy criteria, but I don’t rely solely on it.”
If a child presents with Spitzoid-looking lesion, biopsy is generally preferred to observation. “The traditional belief was that punch biopsy was preferable, followed by shave biopsy,” she said. “This is always on a case-by-case basis.”
However, results from a retrospective study of the records of 123 cases of biopsy-proven Spitz nevi with incomplete removal on biopsy suggests that the method of biopsy matters. The researchers found that the presence of residual lesion in the re-excision specimen was significantly higher when the initial biopsy was done by punch biopsy (90.9%) when compared with shave biopsy (48.9%) and formal excision (62.5%; P < .05).
“This suggests that shave may better than punch for the initial biopsy, but the study was limited by its retrospective design,” Dr. Piggott said at the meeting, which was hosted by Scripps Cancer Center. “Even today it remains controversial whether you should do a shave or punch biopsy.”
Parameters for diagnosing Spitzoid tumors that pathologists look for under the microscope are asymmetry, Clark’s level IV/V, lack of maturation, solid growth, nuclear pleomorphism, high nuclear-cytoplasmic ratio, and mitoses that are atypical, deep, or that exceed 6 mm2 in size.
In terms of treatment recommendations for children with biopsy-proven Spitz nevi, Dr. Piggott said that there is no consensus among pediatric dermatologists. If the biopsy comes back as a benign Spitz nevus, the most reasonable approach is observation, “especially if there is no clinical residue — no pigment on exam, no papule left over in the scar,” she said. “You also want to educate the family about the rare potential for transformation down the line. Monitor for recurrence and consider re-excision if recurrence occurs.”
If the initial Spitz nevus biopsy reveals any degree of atypia, excision is preferred. “In young children, you have to weigh the risks of anesthesia for removal,” she said. “If you’re unable to excise the lesion, close observation is recommended at 6 months or 1 year.”
Treatment for borderline atypical Spitz tumor is excision, she continued, but no outcomes data exist that document a survival benefit with sentinel lymph node (SLN) biopsy. “The decision on whether to do a SLN biopsy is usually made on a case-by-case basis,” Dr. Piggott said. “Nodal metastases from atypical Spitzoid tumors are not uncommon, but death from widespread disease is rare. If the SLN biopsy is positive, complete lymphadenectomy is associated with increased risk of morbidity and no evidence of increased survival. If lymph node disease is found, we in pediatric dermatology would consider referral to a pediatric oncologist for consideration of systemic therapy such as interferon or a newer immunotherapy.”
Dr. Piggott reported having no relevant disclosures.