Dermatology Online Journal

Letter: Acral-lentiginous melanoma: Report of 15 cases
AM Manganoni¹, F Facchetti², F Gavazzoni¹, C Farisoglio¹, G Manca³, E Sereni¹, D Marocolo², PG Calzavara-Pinton¹
Dermatology Online Journal 17 (1): 15

1. Department of Dermatology
2. Department of Pathology I
3. Department of Plastic Surgery
University Hospital Spedali Civili, Brescia, Italy. manganoni@spedalicivili.brescia.it

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Acral Lentiginous Melanoma (ALM) is responsible for approximately 4 percent of all melanomas [1]. It usually occurs on the hairless skin of the palms and soles and in the ungual and periungual regions, the soles being the most common site. ALM is characterized by a radial growth phase evolving to a vertical invasive stage over months or years [2]. The radial growth phase shows a lentiginous pattern of atypical melanocytes, which may look misleadingly benign [3, 4]. A delayed diagnosis is frequent and a misdiagnosis rate higher than 20 percent has been reported [5].

From January 1, 1982 to November 1, 2010, at the Melanoma Unit of University Hospital Spedali Civili of Brescia (Italy), we have observed 2098 patients with histologically confirmed melanoma, 15 of which were diagnosed with cutaneous ALM (0.76%). In two of these fifteen patients a family history of melanoma was present.

Of the fifteen patients, all Caucasian, ten (66.7%) were females and five (33.3%) were males. The mean age was 63.1 years (range 35 to 82). Twelve ALMs (80%) were located on the feet and three on the hands (20%). This predilection for ALM on plantar locations has led to the postulation that trauma is relevant for the development of ALM [5]. In our study, none of the fifteen patients reported pre-lesional trauma. However, it cannot be excluded that the effect of chronic microtrauma, given the location, may somehow contribute to the onset of cancer.

Six cases were classified as melanoma in situ. In the remaining nine patients, Breslow thickness ranged from 0.23 to 3.1 mm with a mean thickness of 1.5 mm. Mean Breslow thickness was higher in males (1.32 mm) than in females (1.08 mm). In two cases a nevus was associated with ALM.

All patients were regularly followed at our institution (average follow-up: 8 years; range 1-25 years). A single patient (whose tumor had a Breslow thickness of 1.9 mm) died after 36 months from cerebral and pulmonary metastases. In none of the remaining fourteen patients (mean Breslow thickness: 0.86 mm) were local recurrences or metastases recorded.

Interestingly, all tumors were first diagnosed at our Melanoma Unit during routine screening for pigmented lesions or general dermatological examination; this emphasizes the important role of dermatologists in detecting early stage melanoma.

References

1. Ridgeway CA, Hieken TJ, Roman SG et al. Acral lentiginous melanoma. Arch Surg 1995;130:88-92. [PubMed]

2. Cascinelli N, Zurrida S, Galimberti V et al. Acral lentiginous melanoma. A histological type without prognostic significance. J Dermatol Surg Oncol 1994; 20;817-22. [PubMed]

3. Paladugu RR, Winber CD, Yonemoto RH. Acral-lentiginous melanoma. A clinicopathologic study of 36 patients. Cancer 1983; 52: 161-168. [PubMed]

4. Arrington JH, Reed RJ, Ichinose H, Krementz ET. Plantar lentiginous melanoma: a distinctive variant of human cutaneous malignant melanoma. Am J Surg Pathol 1977; 1: 131-143. [PubMed]

5. Phan A, Touzet S, Dalle S et al. Acral lentiginous melanoma: a clinicoprognostic study of 126 cases. Br J Dermatol 2006; 155: 561-569. [PubMed]

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