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Dermoscopic clues in the diagnosis of amelanotic and hypomelanotic malignant melanoma.
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PMID:  23197217     Owner:  NLM     Status:  In-Data-Review    
The clinical identification of amelanotic malignant melanoma (AMM) and hypomelanotic malignant melanoma (HMM) becomes difficult due to the lack of pigmentation and to the diverse clinical presentations. Dermoscopy is very useful in these cases, increasing the level of suspicion of malignancy. We report 4 cases of amelanotic malignant melanoma and hypomelanotic malignant melanoma with characteristic dermoscopic findings. Dermoscopy under polarized light demonstrates vascular polymorphism, globules and milky-red areas, in addition to chrysalis and multiple blue-gray dots.
Raquel Bissacotti Steglich; Carolina Degeon Meotti; Mariana Silveira Ferreira; Louise Lovatto; André Vicente Esteves de Carvalho; Carlos Gustavo Carneiro de Castro
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Anais brasileiros de dermatologia     Volume:  87     ISSN:  1806-4841     ISO Abbreviation:  An Bras Dermatol     Publication Date:  2012 Dec 
Date Detail:
Created Date:  2012-11-30     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0067662     Medline TA:  An Bras Dermatol     Country:  Brazil    
Other Details:
Languages:  eng     Pagination:  920-3     Citation Subset:  IM    
Brazilian Society of Dermatology, Porto Alegre, RS, Brazil.
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Journal Information
Journal ID (nlm-ta): An Bras Dermatol
Journal ID (iso-abbrev): An Bras Dermatol
Journal ID (publisher-id): An. bras. dermatol.
ISSN: 0365-0596
ISSN: 1806-4841
Publisher: Sociedade Brasileira de Dermatologia
Article Information
Download PDF©2012 by Anais Brasileiros de Dermatologia
Received Day: 20 Month: 9 Year: 2011
Accepted Day: 10 Month: 2 Year: 2012
Print publication date: Season: Nov-Dec Year: 2012
Volume: 87 Issue: 6
First Page: 920 Last Page: 923
PubMed Id: 23197217
ID: 3699915
DOI: 10.1590/S0365-05962012000600019

Dermoscopic clues in the diagnosis of amelanotic and hypomelanotic malignant melanoma*
Raquel Bissacotti Steglich1
Carolina Degeon Meotti1
Mariana Silveira Ferreira2
Louise Lovatto3
André Vicente Esteves de Carvalho4
Carlos Gustavo Carneiro de Castro5
1M.D., Dermatologist. Member of the Brazilian Society of Dermatology - Porto Alegre (RS), Brazil
2Medical student. - Medical student at the Federal University of Rio Grande do Sul (UFRGS) - Porto Alegre (RS), Brazil
3Master of Medical Clinical Sciences, University of Barcelona, Spain. - Dermatologist at the Irmandade da Santa Casa de Misericórdia de Porto Alegre (ISCMPA) - Porto Alegre (RS), Brazil
4Masters Degree in Pathology - Federal University of Health Sciences of Porto Alegre (UFCSPA) - Porto Alegre (RS), Brazil. - Dermatology preceptor at the Irmandade da Santa Casa de Misericórdia de Porto Alegre (ISCMPA) - Porto Alegre (RS), Brazil
5Medical Doctor - Specialist in Dermatology - Private practice - Rio de Janeiro (RJ), Brazil
Correspondence: Mailing address: Raquel Bissacotti Steglich, Irmandade da Santa Casa de Misericórdia de Porto Alegre, Rua Professor Annes Dias, 295, 90020-090 - Porto Alegre, RS, E-mail:


The incidence of cutaneous melanoma has increased considerably during the last decades in the whole world.1 Its aggressive behavior and the difficulty to treat in advanced stages makes early diagnosis crucial.2

AMM and HMM lesions represent approximately 2 to 8 % of all melanomas, presenting without or with little pigmentation, respectively.3,4,5 The scarcity of pigmentation makes these type of tumor hard to identify, making clinical diagnosis difficult. Dermoscopy is a major instrument allowing the evaluation of pigment, and above all determining characteristic vascular structures, unseen by naked eye.3 Such vascular patterns have an important role on the suspicion of melanoma in doubtful nonpigmented lesions.


Patient 1: A 55-year-old female shows an infiltrated, pseudo-vesicular plaque with well defined borders, 2 X 1,5cm of diameter, on the proximal region of the left arm (Figure 1). Small erythematous papules are seen on the periphery of the lesion. Dermoscopy under polarized light (DPL): chrysalis, linear-irregular vessels, globules and milky-red areas (Figures 2 and 3). Histopathology: nodular AMM, Breslow 11,0 mm, Clark V, with epidermotropic melanoma metastasis. Simultaneously, presents basal cell carcinoma (BCC) on the frontal region.

Patient 2: A 63-year-old male with a history of BCC and squamous cell carcinoma (SCC) in the past presents with an erythematous papule with a bright and smooth surface on the left flank (Figure 4A). DPL: milky-red areas and globules, linear-irregular vessels and residual blue pigmentation (Figure 4B). The contact dermoscopic exam shows disappearance of the central pinkish area and consequent white structureless area (Figure 4C). Histopathology: nodular HMM, Breslow 2,5 mm, Clark IV. BCC and SCC on the trunk.

Patient 3: A 65-year-old male with history of previous melanoma and BCC presents with an erythematous plaque, 1,0 cm in diameter, on the left scapular region. DPL: milky-red areas, central depigmentation, peripheral brown structureless area, dotted and linear-irregular vessels (Figure 5). Histopathology: superficial spread HMM on vertical growing stage, Breslow 1,16 mm , Clark IV.

Patient 4: A 63-year-old female with history of previous BCC shows on her left thigh a 1,6 x 1,5 cm erythematous plaque, with a nodule on its inferior portion. Dark-blue areas are seen on less than 25% of the lesion (Figure 6). DPL: milky red areas, linear irregular vessels, remaining dark-blue pigmentation and chrysalis (Figure 7 and 8). Histopathology: nodular ulcerated HMM, Breslow 3,3 mm, Clark IV.


AMM and HMM present as primary melanomas, recurrent melanomas or metastasis of pigmented primary melanomas. These lesions can occur without the features commonly seen in other melanomas, such as asymmetry and altered pigmentation, often leading to misdiagnosis and inappropriate treatment.5,6 Dermoscopic evaluation has been shown to be superior to naked eye examination for the diagnosis of AMM and HMM.3

Residual pigmentation can be seen as blue or grayish areas, pigment network and brown, gray or black dots and globules.7 Upon dermoscopic inspection AMM have no melanin pigmentation (light brown, dark brown, blue, gray, black). HMM may present as partially pigmented lesions with melanin pigmentation area of less than 25% of the total surface area; or as light-colored lesions with only light brown, light blue, or light gray pigmentation that may occupy more than 25% of total surface area - no dark brown, deep blue, or black pigmentation is found.3

Macroscopically, AMM and HMM can be confused with BCC, SCC, Paget's disease and benign lesions of dermatitis, pyogenic granuloma and plantar wart.4 The reported patients had history or coexistence of BCC and/or SCC. Dermoscopic evaluation was essential for the correct diagnostic suspicion and proper management.

Vascular pattern can increase the level of suspicion of AMM and HMM and it varies according to the level of invasion of the melanoma.7,8,9 Melanoma can initially show dotted vessels and, as the thickness increases, the vascular polymorphism increases with hairpin and linear-irregular vessels associated with milky-red areas, reticular depigmentation and chrysalis.8 Such vascular patterns can only be accurately determined through dermoscopic examination of the lesions. Considering the reported cases on this article, the only cases that presented chrysalis were the patients 1 and 4, who presented the thickest tumors (Breslow 11,0 mm and 3,3 mm).

Several dermoscopic vascular patterns are observed in different types of benign and malignant tumors. 8 Dotted vessels represent a significant marker of melanocytic lesions, with a positive predictive value (PPV) of 90%, and are considered the best dermatoscopic indicator of the melanocytic origin of a tumor. This vascular pattern can be the only clue to suspect a AMM, however, it can not be considered a pathognomonic sign, since it is present in benign lesions.4,7,9 Irregular linear vessels and milky-red areas have a PPV of 68% and 77% in the diagnosis of melanoma, respectively.8

The combination of dotted vessels and linear irregular vessels presents itself as the most frequent dermoscopic finding of AMM.3,4 Although AMM and HMM are still a challenge in clinical practice, dermoscopy can reveal characteristic vascular structures, improving the diagnostic accuracy and being the key to the diagnosis of melanoma. This technique should be used routinely not only to pigmented but also to doubtful nonpigmented lesions.


Conflict of interest: None

Financial funding: None

fn01* Work performed at the Irmandade da Santa Casa de Misericórdia de Porto Alegre (ISCMPA) - Porto Alegre (RS), Brazil.

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4. de Giorgi V,Sestini S,Massi D,Maio V,Giannotti B. Dermoscopy for "true" amelanotic melanoma: A clinical dermoscopy-pathologic case studyJ Am Acad DermatolYear: 20065434134416443072
5. Moloney FJ,Menzies SW. Key points in the dermoscopic diagnosis of hypomelanotic melanoma and nodular melanomaJ Am Acad DermatolYear: 2011381015
6. Puig S,Argenziano G,Zalaudek I,Ferrera G,Palou J,Massi D,et al. Melanomas that failed dermoscopic detection: a combined clinicodermoscopic approach for not missing melanomaDermatol SurgYear: 2007331262127317903162
7. Zalaudek I,Kreusch J,Giacomel J,Ferrara G,Catricalà C,Argenziano G. How to diagnose nonpigmented skin tumors: a review of vascular structures seen with dermoscopy: part I. Melanocytic skin tumorsJ Am Acad DermatolYear: 20106336137420708469
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9. Pizzichetta MA,Canzonieri V,Massarut S,Baresic T,Borsatti E,Menzies SW. Pitfalls in the dermoscopic diagnosis of amelanotic melanomaJ Am Acad DermatolYear: 20106289389420398822


[Figure ID: f01]

Erythematous plaque with an irregular surface on the left arm with satellite small papules

[Figure ID: f02]

Dermoscopic image shows linear-irregular vessels (square), milky-red areas (asterisk) and globules (arrows)

[Figure ID: f03]

Dermoscopic evaluation revealing chrysalis (arrows)

[Figure ID: f04]

(A) Erythematous papule on the left flank. (B) Vascular polymorphism and residual pigmentation at dermoscopy. (C) Dermoscopic examination shows vascular polymorphism (square), blue residual pigmentation (asterisk) and milky-red areas (arrow)

[Figure ID: f05]

(A) Erythematous plaque on the left scapular region. (B) Milky red areas (arrows), central depigmentation, brown structureless area at the periphery (asterisk), linear-irregular vessels (circle) and dotted vessels (square)

[Figure ID: f06]

Erythematous plaque, with a nodule on its inferior portion. Some dark-blue areas are seen on less than 25% of the lesion

[Figure ID: f07]

The non-contact dermoscopic exam shows milky red areas (asterisk), atypical vessels (square)

[Figure ID: f08]

The contact dermoscopic exam shows milky red areas (arrows), linear irregular vessels (circle), remaining dark-blue pigmentation (asterisk) and chrysalis (bold arrow)

Article Categories:
  • Imaging In Dermatology

Keywords: Dermoscopy, Diagnosis, Diagnosis, differential, Melanoma, Melanoma, amelanotic.

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