An Asymptomatic, Small, Pinkish Plaque on the Arm of a Female Elderly Patient

Abstract

A 79-year-old female patient presented to our clinic for a six -months history of an asymptomatic lesion on her right arm.

Clinical examination revealed a pinkish, indurated plaque with peripheral foci of grey- brown pigmentation and superficial scaling, measuring 0.8 × 1.0 cm. Figure 1.

Dermoscopic examination revealed asymmetric shape, scaling, polymorphic vessels, central depigmentation and focal pigmentation on the periphery. Figure 2.

Upon clinical examination, the slowly growing, pinkish, indurated plaque with peripheral pigmentation and superficial scaling pointed towards the differential diagnosis of Bowen's disease (BD), basal cell carcinoma (BCC) and amelanotic—hypomelanotic melanoma (AHM). The detailed dermoscopic examination revealed asymmetric shape, scaling, multiple colors, polymorphic vessels that included dotted vessels mainly in the periphery and linear irregular vessels located centrally, scar-like central depigmentation and focal irregular pigmentation on the periphery with atypical pigment network and atypical globules. Figure 2. These findings excluded BCC and narrowed the differential diagnosis between BD and AHM.

Dermoscopic findings of dotted vessels, scaling and pigmentation are observed both in BD and AHM, and careful analysis of subtle differences is needed to distinguish between them. In our patient, the dermoscopy photo was carefully examined and discussed between two consultant dermatologists. In BD, vessels are described as “glomerular” which are usually larger in size, looped and regularly arranged in clusters while pigmented globules are usually smaller and scattered throughout the lesion [1].

The combination of dotted and linear irregular vessels, scar-like central depigmentation and atypical pigment network and globules, pointed to the diagnosis of hypomelanotic melanoma which was confirmed by histology.

The lesion was excised with a 2.0 mm peripheral skin margin. Histological examination as shown in Figure 3, revealed atypical melanocytes infiltrating the papillary dermis as nests and solitary units with a pagetoid pattern. Histology and immunohistochemistry confirmed the diagnosis of stage pT1a/N0/M0 malignant melanoma: Breslow 0.55 mm, one mitosis/mm2, diffuse lymphocytic infiltration, absence of histological ulcerations, melan-A (+) and HMB45 (+). The patient underwent surgical re-excision with 1.0 cm peripheral skin margin and was regularly followed up thereafter.

Amelanotic and hypomelanomatic melanomas (AHMs) are estimated at 2%–8% of all melanomas but it is postulated that their prevalence could be greater due to misdiagnosis [2].

In contrast with the absence of clinical criteria, dermoscopic findings are more specific. In scarcity of pigment, dermoscopy is based on the characteristics of the vasculature. As positive indicators of AHM are reported the combined presence of dotted and irregular linear vessels and their atypical distribution in the periphery of the lesion [1-5]. The type of vessels is indicative of tumor progression: dotted vessels are reported to dominate in early AM, while linear vessels appear in increasing number as the tumor progresses [2].

Upon dermoscopy, in our patient, the presence of both dotted vessels peripherally and linear irregular vessels located centrally was an important clue towards the diagnosis.

In addition to vascular characteristics, other dermoscopic features of AHM include an asymmetric shape, multiple colors, blue-white veil, multiple blue-gray dots, milky red-pink areas, a scar-like depigmentation, and ulceration [3-5]. In our case, the asymmetric shape, multiple colors and a central scar-like depigmentation were present. In addition, we observed foci of atypical pigment network and atypical globules at the periphery, findings that in combination with the above mentioned vessel formations, further supported the diagnosis of HM.

Finally, the prominent scaling in our case has been identified as a common clinical feature of AHM and BD in numerous case reports. In AHM, scaly appearance is thought to be the result of increasing differentiation and proliferation of keratinocytes triggered by neoplastic melanocytes [1, 2].

Six months after her dermatology visit, at a presymptomatic screening the patient was diagnosed with carcinoma of the right breast which was surgically removed. Histological and immunohistochemical examination revealed malignant ductal breast carcinoma of nonspecific type, 9.0 mm diameter, stage 2, with negative local lymph nodes.

Epidemiological studies report an elevated risk of developing second primary cancers (SPCs) in patients with a previous cancer diagnosis. Standardized incidence ratio (SIR) ranged from 1.03 to 4.10 for primary breast carcinoma after cutaneous melanoma. The risk is reported as higher within a year of melanoma diagnosis [6].

The predominant theories for this correlation are the presence of common tumor susceptibility genes such as BRCA2 and CDK2NA, biological factors such as oestrogen exposure and surveillance bias [6].

In our patient, breast cancer was detected at a routine mammography 6 months after the initial diagnosis of AHM. In Greece, the National Breast Cancer Screening Program provides a free annual Digital Mammography to all women aged 45–74. Our patient, although 79 years old continued her annual screening and was even more encouraged to do so after the melanoma diagnosis.

Our elderly patient was not subjected to oestrogens. The possible mechanisms for the SPC she developed in the right breast 6 months after the AHM diagnosis, include surveillance bias and genetic factors.

Dermoscopy should be regarded as routine examination of lesions that persist longer than 1 month. It is cheap, readily available, easy to apply and with the advance of dermoscopic technology, visualization is of better quality. Recognition of suspicious lesions is enhanced with adequate training and is of primary importance.

Patients with a diagnosis of AHM should be screened for SPCs, even at an advanced age.

Despina Exadaktylou: overall responsibility for the integrity of the entire work, from inception to the published article: Conceptualization, design, investigation, data acquisition, analysis and interpretation, writing–original draft, writing–review and editing. Kanella Kalapothakou: data acquisition, critically revising the article for important intellectual content, final approval of the version to be published. Niki Arnogiannaki: data analysis, critically revising the article for important intellectual content, final approval of the version to be published. Evelina Skafida: data interpetation, critically revising the article for important intellectual content, final approval of the version to be published. Spyridon Stavrianos: data acquisition, critically revising the article for important intellectual content, final approval of the version to be published.

The patient in this manuscript has given written informed consent for participation in the study and the use of her deidentified, anonymized, aggregated data and her case details (including photographs) for publication. Ethical Approval: not applicable.

The authors declare no conflicts of interest.