Journal List > J Korean Soc Surg Hand > v.21(4) > 1106543

J Korean Soc Surg Hand. 2016 Dec;21(4):238-242. English.
Published online December 26, 2016.  https://doi.org/10.12790/jkssh.2016.21.4.238
Copyright © 2016. The Korean Society for Surgery of the Hand
Nodular Melanoma on the Tip of the Thumb
Su Hyun Choi, Hong Bae Jeon and Ja Hea Gu
Department of Plastic Surgery, Dankook University Hospital, Cheonan, Chungnam, Korea.

Correspondence to: Ja Hea Gu. Department of Plastic Surgery, Dankook University Hospital, 201 Manghyang-ro, Dongnam-gu, Cheonan 31116, Korea. TEL: +82-41-550-3873, FAX: +82-41-554-6477, Email: jaheagu@gmail.com
Received September 21, 2016; Revised November 16, 2016; Accepted November 23, 2016.

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.


Abstract

Nodular type malignant melanoma is uncommon in fingers. In previous publications, treatment, diagnosis and case reports of subungal melanoma is often, however fingertip lesion was not focused. A 64-year-old woman who had a non-healing red and dark colored nodular mass with ulceration over the finger tip in the right thumb visited our clinics. Biopsy results was malignant melanoma then we performed amputation surgery of distal phalanx. Lymph node biopsy and resection margin was negative for melanoma. Chemotherapy was administered immediately. After 5 months, pulmonary nodular lesion was found and diagnosed as metastatic malignant melanoma by the wedge resection surgery. The patient is treated for additional chemotherapy consistently and disease free for 2 years. Nodular type melanoma of the finger is uncommon and it could be presented as ulceration and amelanotic nodular mass. Therefore we recommend biopsy to diagnose correctly if there are chronic non healing lesions on the fingers.

Keywords: Melanoma; Nodular melanoma; Chronic ulcer; Finger tip

INTRODUCTION

The occurrence of malignant melanoma on fingers is rare; however melanoma of the finger is a highly malignant tumor with rapid disease progression1. Acral malignant melanoma has a low incidence, accounting for 5% of total malignant melanomas1. Pathological symptoms are characterized by acral splash melanoma, early radioactive growth, shallow invasion and less likelihood of metastasis. Early treatment normally results in a favorable prognosis. In the late stage, the tumor exhibits vertical growth, a high rate of lymph node metastasis and poor prognosis. However, early clinical symptoms of these patients are mild and easily overlooked. In addition, patients can easily access their wounds, then they themselves treat their minor wounds, and the primary physician can misdiagnose the condition as it is a nonspecific small lesion and it could be misunderstood as a minor traumatic lesion or pyogenic granuloma.

In melanomas, both clinical presentation and dermatoscopical features are extremely variable2. Melanomas have dermatoscopical features indicating their melanocytic origin, such as pigment, aggregated brown or black globules, and site specific features on palms and soles. However in some cases, a melanoma may be clinically and dermatoscopically relatively featureless, and in such cases even experienced dermatologists may have difficulty recognizing the melanoma. In previous publications, treatment, diagnosis and case reports of subungual melanoma were frequently reported; however, there was no focus on the fingertip lesion3.

We report a case of a nodular type malignant melanoma in a 64-year-old woman, whose major complaints were skin ulceration and nodular lesion. The aim of this case report is to emphasize that in the differential diagnosis of skin lesions that take a longer time to heal, or in cases of an amelanotic mass of unknown origin, it is necessary for clinicians to take malignant melanoma into consideration as a potential diagnosis.

CASE REPORT

A 64-year-old woman visited our clinic with a complaint of a non-healing ulcer lesion over the ulnar side of the tip of the right thumb for 3 weeks. It appeared to have started as a nodule which had developed 9 months ago. The nodule gradually increased in size, and it caused pain and swelling with bullae on her right thumb. She tried to remove the bullae herself, but the lesion did not resolve. On physical examination, the lesion was 5mm in diameter and its surface was red and dark in color and ulcerated (Fig. 1). There were no signs of infection. Based on the clinical appearance, a diagnosis of pyogenic granuloma was suspected and excisional biopsy was performed.


Fig. 1
Preoperative view. The lesion was 5 mm in diameter and its surface was red and dark color, ulcerated.
Click for larger image

There was a dark colored nodular lesion inside the ulceration (Fig. 2). Histological examination revealed a malignant melanoma. Three pathologists reviewed the slides to confirm the diagnosis because of the presence of rare melanocytes (Fig. 3). Tumor depth was 5.5 mm and tumor cells with ulceration were positive for melanocytic markers. One week later, magnetic resonance imaging showed that postoperative scar tissue was detected on the ulnar side of the tip of the right thumb and there was no lesion infiltrating into the bone marrow space. We performed amputation surgery on interphalangeal joint level by institutional tumor board's recommendation considering patient size and lesion location (Fig. 4). In addition, axillary sentinel lymph node biopsy was performed. Frozen section reported that there was absence of melanoma in the lymph node and amputated product. Positron emission tomography–computed tomography (PET-CT) was done to evaluate of distant metastasis. The result demonstrated small sized pulmonary nodular opacity in right lower lobe posteior basal segment and the size was too small to characterize. A few small sized lymph nodes with fat hilum along right axillary area without significant fluorodeoxyglucose uptake seemed to be reactive lymphadenitis. Chest CT scan found no evidence of metastasis with linear subsegmental atelectasis in left lower lobe. According to these results, this lesion was staged on II-c.


Fig. 2
Intraoperative finding. (A) Nodular lesion was found inside the small ulceration (B) Diameter of the nodule was about 5.5 mm.
Click for larger image


Fig. 3
Microphotograph of the tumor. (A) Low-power magnification reveals dermal infiltration of tumor cells with abundant brownish pigment and skin ulceration (H&E stain, ×40). (B) Higher magnification of tumor cells demonstrates marked nuclear pleomorphism with macronucleoli (H&E stain, ×200).
Click for larger image


Fig. 4
Postoperative finding. Amputation was done at interphalangeal joint level. (A) Volar side view of amputated thumb. (B) Dorsal view of stump.
Click for larger image

Chemotherapy was administered immediately after the diagnosis of melanoma. However, contrast-enhanced computed tomography of the chest showed a nodular lesion in the right middle lobe, a finding that suggested the presence of metastases after 5 months. The nodular lesion was diagnosed as metastatic malignant melanoma by wedge resection surgery. The clinical findings of the patient and appearance of the masses were consistent with the diagnosis of nodular melanoma. The patient is being treated with chemotherapy consistently and no recurrence was detected for 2 years.

DISCUSSION

Acral lentiginous melanoma is the least common type among the 4 types of melanoma. However, it is a common type of melanoma among Asians and dark-skinned individuals2. It is known to affect the glabrous skin, and it has a predilection for palms, soles and subungual areas. Furukawa et al.3 and Kato et al.4 reported 15 and 34 cases of thumb melanoma and all these cases were located on the subungual or proximal site. Kuchelmeister et al.5 reported 112 cases of acral cutaneous melanoma in Caucasians and they showed that these acral type of melanomas were located on the palmar, plantar, subungual, and dorsal sites of the hands and feet. Nine percent of the nodular type of melanoma was detected, then authors suggested nodular melanoma could be occur on acral site. However, the lesion was limited on the palmar, plantar, subungal and dorsal site of the extremities. Finger tip melanoma is very rare, and it has not been focused or reported previously.

In this case, the patient overlooked her lesion and tried to remove it herself. The nodular lesion was increased in size and it caused painful swelling and ulceration. Based on the clinical appearance, a diagnosis of pyogenic granuloma was suspected and excisional biopsy was planned. However, during the operation, the authors found that the nodule was dark colored, and hence, malignant melanoma was suspected. As in a previous report, the patient was already in an advanced stage1. In order to make an early diagnosis, provide early treatment, and improve the survival period, a biopsy should be performed in all cases of suspected malignant melanoma of the finger that present with expanded areas of black patches, darkening of the patches, and appearance of uneven borders. The treatment of principal in digital melanoma for this patient was amputation at one joint proximal to the melanoma along with sentinel node biopsy. Authors followed this protocol6.

In conclusion, melanoma of the finger tip is uncommon and it could present with a nevus, ulceration, an amelanotic nodular mass, and pain. Therefore, we recommend biopsy for correct diagnosis, if there is a chronic non-healing lesion on the fingers.

References
1. Yang Z, Xie L, Huang Y, et al. Clinical features of malignant melanoma of the finger and therapeutic efficacies of different treatments. Oncol Lett 2011;2:811–815.
2. Situm M, Buljan M, Kolic M, Vucic M. Melanoma: clinical, dermatoscopical, and histopathological morphological characteristics. Acta Dermatovenerol Croat 2014;22:1–12.
3. Furukawa H, Tsutsumida A, Yamamoto Y, et al. Melanoma of thumb: retrospective study for amputation levels, surgical margin and reconstruction. J Plast Reconstr Aesthet Surg 2007;60:24–31.
4. Kato T, Suetake T, Sugiyama Y, Tabata N, Tagami H. Epidemiology and prognosis of subungual melanoma in 34 Japanese patients. Br J Dermatol 1996;134:383–387.
5. Kuchelmeister C, Schaumburg-Lever G, Garbe C. Acral cutaneous melanoma in caucasians: clinical features, histopathology and prognosis in 112 patients. Br J Dermatol 2000;143:275–280.
6. Kozlow JH, Rees RS. Surgical management of primary disease. Clin Plast Surg 2010;37:65–71.