Nodular malignant melanoma with Spitz nevus-like pathological features finally confirmed by the pathological feature of the sentinel lymph node

Atypical Spitzoid neoplasms: a review of potential markers of biological behavior including sentinel node biopsy

Atypical cutaneous melanocytic lesions, including those with Spitzoid features, can be difficult to categorize as benign or malignant. This can lead to suboptimal management, with potential adverse patient outcomes. Recent studies have enhanced knowledge of the molecular and genetic biology of these lesions and, combined with clinicopathological findings, is further defining their biological spectrum, classification, and behavior. Sentinel node biopsy provides important prognostic information in patients with cutaneous melanoma, but its role in the management of melanocytic lesions of uncertain malignant potential (MELTUMP) is controversial. This paper examines the role of molecular testing and sentinel node biopsy in MELTUMPs, particularly atypical Spitzoid tumors.

Long-term outcome of Spitz-type melanocytic tumors

OBJECTIVE

Despite recent advances in our molecular understanding of Spitz-type tumors, the clinical behavior of these lesions remains unclear. We thus set out to define the clinical outcome of classic Spitz nevi, atypical Spitz tumors (ASTs), and spitzoid melanomas.

DESIGN

From 1987 through 2002, data on all lesions containing the term "Spitz" or "Spitz" [AND] "melanoma" were retrieved from the pathology database at Massachusetts General Hospital, and the cases were followed up for their outcome.

SETTING

The study was performed at a university-affiliated tertiary health care center in Boston, Massachusetts.

PATIENTS

A total of 157 patients with Spitz-type melanocytic lesions and follow-up information were identified.

MAIN OUTCOME MEASURES

Sentinel lymph node biopsy results, metastases, or fatality were assessed.

RESULTS

There were 68 classic Spitz nevi, 76 ASTs, 10 spitzoid melanomas, and 3 melanomas that arose in Spitz nevi. Spitz nevi were diagnosed at a younger age than ASTs (mean age, 26.4 years vs 33.7 years) (P = .01), though both occurred earlier than melanomas (mean age, 50.4 years, P < .001). Sentinel lymph node biopsy findings were positive in 1 of 6 and 4 of 8 patients with ASTs and spitzoid melanomas, respectively. After a median follow-up of 9.1 years, only 1 patient with an AST, who had a separate intermediate-thickness melanoma, developed distant metastasis. There were 6 documented invasive melanomas among 144 patients with classic Spitz nevi or ASTs (observed/expected ratio, 8.03) (P = .01).

CONCLUSIONS

Atypical Spitz tumors are associated with minimal lethal potential, an increased melanoma risk, and a moderate risk of metastasis to regional nodes. It makes clinical sense to minimize aggressive treatment but to offer careful surveillance for rare relapses and subsequent melanomas.

Atypical spitzoid melanocytic tumors with positive sentinel lymph nodes in children and teenagers, and comparison with histologically unambiguous and lethal melanomas

Children and teenagers with a positive sentinel lymph node (SLN) after a prior diagnosis of an atypical spitzoid melanocytic tumor (ASMT) are usually cared for clinically in the same way as patients with melanoma. Little is known about long-term follow-up of these individuals to determine whether this practice is appropriate. To learn more about the biology of these tumors we retrospectively reviewed the clinical and pathologic findings of children and teenagers (<18 y of age at the time of diagnosis) with an ASMT, positive SLN and follow-up of at least 3 years. Their findings were compared with histologically unambiguous melanomas of children or teenagers, who had a positive SLN or died of metastatic melanoma. Eleven individuals, 6 girls and 5 boys, with primary ASMT and positive SLN were identified. The primary tumors ranged in thickness from 2.1 to 12 mm (median, 4.6 mm; mean, 5 mm). The tumor mitotic rate ranged from 1 to 10 mitoses/mm (median, 3/mm, median, 3/mm). The positive SLNs included 6 nodes with intranodal melanocytic aggregates measuring <1 mm in greatest dimension, and 5 nodes, in which the size of the melanocyte deposits was >/=1 mm. All the patients with ASMT and positive SLN remained free of disease with a median follow-up of 47 months (mean, 61 mo, range: 36 to 132 mo). In contrast, 2 of 5 patients <18 years of age with a histologically unambiguous melanoma and a positive SLN died of metastatic melanoma. The overall disease-specific mortality rate for all patients <18 years of age diagnosed with melanoma was 12%. Our findings confirm that children and teenagers with ASMTs and positive SLNs have a less aggressive clinical course than those with histologically unambiguous melanoma.

Sentinel lymph node biopsy in pediatric and adolescent cutaneous melanoma patients

BACKGROUND

The rarity of melanoma in young patients, particularly pediatric ones, has to date precluded any valid comparisons being made between young patients and adults undergoing sentinel lymph node biopsy (SLNB) for intermediate thickness localized melanoma. The present study takes advantage of the large Sydney Melanoma Unit (SMU) database to clarify this issue.

MATERIALS AND METHODS

Clinical and pathologic data on pediatric and adolescent AJCC Stage I and II cutaneous melanoma patients aged <20 years undergoing SLNB at the SMU between January 1993 and February 2008 were reviewed. SLNB positivity rates and outcomes in these patients were compared with adult SMU patients.

RESULTS

In 55 young patients, overall median tumor thickness was 1.7 mm (range, 0.6-5.2 mm) and overall SLNB positivity rate was 14 of 55 (25%), tumors tending to be thicker (median, 2.6 mm), and SLNB positivity rate higher (2 of 6; 33%) in patients aged <10 years. Of the 14 patients, 13 underwent immediate completion lymph node dissection (CLND); 2 patients had non-SLN metastases (15.4%). Only 0.7% of a total of 295 lymph nodes removed at CLND were involved with melanoma. In 14 SLNB-positive patients with follow-up data, 3 (21%) have died from melanoma after a median follow-up of 60 months, compared with 42% of 356 SLNB positive adults.

CONCLUSIONS

Although the SLNB positivity rate was higher in pediatric and adolescent melanoma patients than in adults (25% vs. 17%, respectively), non-SLN positivity and melanoma-specific death rates were low.

The atypical Spitz tumor of uncertain biologic potential: a series of 67 patients from a single institution

BACKGROUND

Atypical Spitz tumors (AST) are rare spitzoid melanocytic proliferations with an uncertain malignant potential. ASTs have overlapping features of both Spitz nevi and spitzoid melanoma, and consequently generate controversy with diagnosis and management. Sentinel lymph node biopsy (SLNB) has been proposed as a possible means to gain additional insight into the true biologic potential of these tumors; however, previous reports on the use of SLNB in ASTs have been limited by small numbers of patients and short durations of follow-up.

METHODS

The authors extracted data from their institution's prospective melanoma database, collected between 1994 and 2007, for all patients with ASTs of uncertain biologic potential. They reviewed the clinical features of these patients, including the sentinel lymph node status, and the histological features of the tumors.

RESULTS

A total of 67 patients with ASTs were identified, with a median age of 23.7 years. The mean depth was 2.4 mm. Of these, 57 had a SLNB performed, with 27 (47%) having a positive sentinel lymph node. SLNB-positive cases had a significantly lower mean age than SLNB-negative cases (17.9 vs 28.7 years; P = .013); however, no other significant differences were observed. All 27 patients with a positive SLNB were alive and disease free with median follow-up of 43.8 months. One patient who did not receive a SLNB developed recurrent disease with regional and distant metastases.

CONCLUSIONS

ASTs do not appear to behave like conventional melanoma. There is a high incidence of microscopic lymph node deposits in SLNBs, but despite this finding, patients have a favorable prognosis. Our findings raise several questions regarding the malignant potential of ASTs, and the role of SLNB in their management.

Sentinel lymph node biopsy for patients with diagnostically controversial Spitzoid melanocytic tumors?

The distinction of a Spitz nevus from melanoma can be very difficult. Pathologists may disagree on whether a Spitzoid melanocytic proliferation is benign or malignant, or acknowledge uncertainty about the diagnosis. As long as melanoma is suspected or strongly considered, a clinical management plan is often adopted as if the patient had melanoma, which may include sentinel lymph node (SLN) biopsy for staging. The findings of the sentinel node may resolve the diagnostic controversy about the primary tumor, but there is also the risk for more diagnostic confusion, uncertainty, and errors. We review the arguments in favor and against SLN biopsy for patients with diagnostically controversial Spitzoid melanocytic tumors, summarize current experience, and illustrate diagnostic pitfalls. Although SLN biopsy provides prognostic information helpful for clinical trials, we caution against performing the procedure as a diagnostic adjunct.