Pitfalls in the dermoscopic diagnosis of amelanotic melanoma Massimo Mascolo, MD, PhD,a Daniela Russo, MD,a Massimiliano Scalvenzi, MD,b Silvia Varricchio, BTD,a and Stefania Staibano, MD, PhDa Naples, Italy
CLINICAL PRESENTATION A 68-year-old man presented with a rapidly growing, reddish, 8- 3 6-mm nodule on his left thigh that had appeared 2 months before admission (Fig 1).
Fig 1. Clinical findings.
DERMOSCOPIC APPEARANCE Dermoscopy revealed a diffuse structureless area of reddish color associated with an atypical vascular pattern (Fig 2). A skin biopsy specimen was obtained.
Fig 2. Dermoscopic findings. From the Department of Advanced Biomedical Sciences,a Pathology Section, and the Department of Dermatology,b University of Naples Federico II. Publication of this article was supported by 3Gen. Funding sources: None. Conflicts of interest: None declared. Correspondence to: Massimo Mascolo, MD, PhD, Department of Advanced Biomedical Sciences, Pathology Section, University of
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Naples Federico II, Via Pansini, 5, 80131, Naples, Italy. E-mail: [email protected]. J Am Acad Dermatol 2015;72:S2-3. 0190-9622/$36.00 ª 2014 by the American Academy of Dermatology, Inc. http://dx.doi.org/10.1016/j.jaad.2014.02.040
J AM ACAD DERMATOL VOLUME 72, NUMBER 1
Mascolo et al S3
HISTOLOGIC DIAGNOSIS Histology revealed a nodular tumor involving most exclusively the superficial and mid-dermis that was comprised of sheets of epithelioid cells with pleomorphic nuclei, eosinophilic nucleoli, and abundant eosinophilic cytoplasm admixed with a brisk lymphocytic infiltrate. Immunohistochemistry revealed a strong positivity for S100 and MART-1, which confirmed the melanocytic nature of the lesion (Fig 3). A diagnosis of nonulcerated nodular melanoma with a Breslow thickness of 1.9 mm and a mitotic index $ 1 mm/mm2 was made.
Fig 3. Histology of the lesion. Panoramic view of the lesion revealing a nodular infiltrate of neoplastic cells mixed with a brisk lymphocytic infiltrate involving most exclusively the superficial and mid-dermis. (Hematoxylineeosin stain; original magnification: 3100.)
KEY MESSAGE This case illustrates the difficulty of diagnosing hypopigmented/amelanotic melanoma on the basis of only the clinical and dermoscopic features. Although the rapid growth of this lesion was strongly indicative of a malignant tumor, the diffuse reddish homogeneous area associated with the atypical vascular dermoscopic pattern was erroneously interpreted as being suggestive of a vascular tumor. This lesion bears clinical and dermoscopic close similitude to some benign tumors, including dermal nevi, pyogenic granuloma, and angiomas,1 which usually involve the extremities and, at times, can be indistinguishable from amelanotic melanomas. Dermoscopy remains extraordinarily useful for the early detection of amelanotic or slightly pigmented melanoma,2 although it may at times provoke a misdiagnosis, leading to wrong treatment choice.
REFERENCES 1. Zaballos P, Carulla M, Ozdemir F, Zalaudek I, Ba~ nuls J, Llambrich A, et al. Dermoscopy of pyogenic granuloma: a morphological study. Br J Dermatol 2010;163:1229-37. 2. Baroni A, Piccolo V. Images in clinical medicine. Red melanoma. N Engl J Med 2013;368:1536.
CLINICAL PRESENTATION A 68-year-old man presented with a rapidly growing, reddish, 8- 3 6-mm nodule on his left thigh that had appeared 2 months before admission (Fig 1).
Fig 1. Clinical findings.
DERMOSCOPIC APPEARANCE Dermoscopy revealed a diffuse structureless area of reddish color associated with an atypical vascular pattern (Fig 2). A skin biopsy specimen was obtained.
Fig 2. Dermoscopic findings. From the Department of Advanced Biomedical Sciences,a Pathology Section, and the Department of Dermatology,b University of Naples Federico II. Publication of this article was supported by 3Gen. Funding sources: None. Conflicts of interest: None declared. Correspondence to: Massimo Mascolo, MD, PhD, Department of Advanced Biomedical Sciences, Pathology Section, University of
S2
Naples Federico II, Via Pansini, 5, 80131, Naples, Italy. E-mail: [email protected]. J Am Acad Dermatol 2015;72:S2-3. 0190-9622/$36.00 ª 2014 by the American Academy of Dermatology, Inc. http://dx.doi.org/10.1016/j.jaad.2014.02.040
J AM ACAD DERMATOL VOLUME 72, NUMBER 1
Mascolo et al S3
HISTOLOGIC DIAGNOSIS Histology revealed a nodular tumor involving most exclusively the superficial and mid-dermis that was comprised of sheets of epithelioid cells with pleomorphic nuclei, eosinophilic nucleoli, and abundant eosinophilic cytoplasm admixed with a brisk lymphocytic infiltrate. Immunohistochemistry revealed a strong positivity for S100 and MART-1, which confirmed the melanocytic nature of the lesion (Fig 3). A diagnosis of nonulcerated nodular melanoma with a Breslow thickness of 1.9 mm and a mitotic index $ 1 mm/mm2 was made.
Fig 3. Histology of the lesion. Panoramic view of the lesion revealing a nodular infiltrate of neoplastic cells mixed with a brisk lymphocytic infiltrate involving most exclusively the superficial and mid-dermis. (Hematoxylineeosin stain; original magnification: 3100.)
KEY MESSAGE This case illustrates the difficulty of diagnosing hypopigmented/amelanotic melanoma on the basis of only the clinical and dermoscopic features. Although the rapid growth of this lesion was strongly indicative of a malignant tumor, the diffuse reddish homogeneous area associated with the atypical vascular dermoscopic pattern was erroneously interpreted as being suggestive of a vascular tumor. This lesion bears clinical and dermoscopic close similitude to some benign tumors, including dermal nevi, pyogenic granuloma, and angiomas,1 which usually involve the extremities and, at times, can be indistinguishable from amelanotic melanomas. Dermoscopy remains extraordinarily useful for the early detection of amelanotic or slightly pigmented melanoma,2 although it may at times provoke a misdiagnosis, leading to wrong treatment choice.
REFERENCES 1. Zaballos P, Carulla M, Ozdemir F, Zalaudek I, Ba~ nuls J, Llambrich A, et al. Dermoscopy of pyogenic granuloma: a morphological study. Br J Dermatol 2010;163:1229-37. 2. Baroni A, Piccolo V. Images in clinical medicine. Red melanoma. N Engl J Med 2013;368:1536.
