Journal of Plastic, Reconstructive & Aesthetic Surgery (2014) 68, e45ee46
CORRESPONDENCE AND COMMUNICATION Desmoplastic melanoma in a fingertip: A rare entity* Dear Editor, Desmoplastic melanoma (DM) represents a rare variant of skin cancer that is often missed due to absence of any pigmentation and a confusing appearance histologically. It is particularly rare in a fingertip resulting in delayed treatment. We present a misdiagnosed case to raise awareness of DM wishing others to learn from our delays. Our 40 year old female patient was referred from a skin oncology clinic with a 3 year history of swelling on the dorso-ulnar side of the little finger, just proximal to the nail fold. For 2 years it had been intermittently ulcerating. There was no axillary lymphadenopathy. The referring diagnosis was of a mucous cyst (Figure 1), but the senior author disagreed. While uncertain of the diagnosis, differentials included nerve tumours and dermatitis artifacta. The initial MRI demonstrated a well defined extraarticular lesion for which surgical excision was planned. However at surgery no lesion was found, just an area of scarring, which was biopsied. Histology showed fibrotic changes and no malignancy. Even after multiple stains, no clearer diagnosis was forthcoming. At review with a colleague for second opinion, the diagnosis remained uncertain. Due to pain, flexion deformity and ulceration the patient chose to have an amputation. This was done through the middle phalanx, 9 months after original referral. Histology at this stage demonstrated a desmoplastic malignant melanoma with Breslow thickness of 4.5 mm, ulceration, invasion of bone marrow, extensive perineural invasion and incomplete excision at both soft tissue and bony margins. It was strongly Se100 positive, as was the first specimen when later tested. Definitive surgery required ray amputation, performed using Moh’s technique (Figure 2). Skin margins were still involved, therefore it was resected further; this was considered clear on Moh’s histology even though there were scattered cells still staining for Se100.
* This work was in part presented at the ESPRAS 2014, Edinburgh (e-poster) on the 9th July 2014.
DM represents a rare variant of skin malignancy. It is more common in men aged 60e70. Only a third of desmoplastic melanomata occur in upper extremities while exposed areas such as head and neck are affected more frequently (50% of cases).1e4 Due to their bland clinical appearance, only a third of all cases are initially identified as malignant melanoma.1 Up to 70% of desmoplastic melanomata have no visible pigmentation and clinically look like scars or other benign lesions. As a result, like in our case, an incisional rather than excisional tissue biopsy is performed with a tendency to miss the diagnostically most characteristic portion of the lesion and to misinterpret histology, which commonly resembles simple fibroblastic proliferation. In a fingertip this poses a particular challenge: misdiagnosis is common and delay in treatment means more aggressive surgical clearance which can leave the patient incapacitated. Microscopically DM is characterised by melanocytic hyperplasia with intense fibroblastic reaction and presence of spindle cells (melanocytes), which stain strongly for the Se100 protein antigen. The Se100 protein antigen is the most valuable marker to aid the diagnosis of DM.2,3 It exhibits a strong reaction in the actual lesion, but can still be found in the scar already cleared of melanoma.3 Confusingly the Se100 stain is also positive in schwannomata and other nerve tumours.3 Histological findings in our case included fibroblastic reaction but no melanocytic hyperplasia, so our first tissue diagnosis was misinterpreted as scar. It stained for the Se100 at the later histological examination, which helped to diagnose DM.
Figure 1 Pre-operative appearance of the lesion and resulting fingertip deformity.
http://dx.doi.org/10.1016/j.bjps.2014.09.040 1748-6815/ª 2014 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.
e46
Correspondence and communication
Ethical approval N/A.
Financial support No financial support received.
Conflict of interest No conflict of interest to declare.
Written consent Figure 2
Post-operative result.
As seen in our patient, more advanced disease at diagnosis means more aggressive and potentially more incapacitating treatment: the mean Breslow thickness at the time of diagnosis in DM is 2.0e6.5 mm3,4 with half of all lesions being thicker than 4 mm and with only 4% limited to Clark’s level IV.1 Local recurrence rates for a given Breslow’s depth are higher,3e5 but regional recurrence is less common.4,5 In addition, DM presents with neurotropism in up to 78%4 which makes this tumour more difficult to clear and more likely to recur locally.3 Regardless though, 5-year survival rates are relatively good (67e89%3). As with other melanomata, surgical excision is the treatment for DM, which in digits usually means amputation. Excision margins for DM are not established but advised to be wider than in most melanoma variants e at least 2 cm. Due to the rarity of DM, the role of sentinel node biopsy, radiation or any other adjuvant therapy has not yet been determined in desmoplastic variants.3 In summary, desmoplastic melanoma tends to be diagnosed late; in long-standing and thick lesions. Those involved in managing patients with skin disorders should be aware of this clinicopathological variant. This unusual and initially inconspicuous case of DM in a fingertip demonstrates the potential for misdiagnosis and the need for awareness of desmoplastic melanoma in a hand in order to manage it appropriately and in timely manner.
Patient has given written consent to use her clinical photographs for research and publication purposes.
References 1. de Almeida LS, Requena L, Ru ¨tten A, et al. Desmoplastic malignant melanoma: a clinicopathologic analysis of 113 cases. Am J Dermatopathol 2008 Jun;30(3):207e15. 2. Chung KC, Calkins ER, Crawford R, Rees RS. Desmoplastic melanoma of the hand: case reports and review of the literature. J Hand Surg Am 1995 Sep;20(5):873e6. 3. Chen LL, Jaimes N, Barker CA, Busam KJ, Marghoob AA. Desmoplastic melanoma: a review. J Am Acad Dermatol 2013 May; 68(5):825e33. 4. Lens MB, Newton-Bishop NJ, Boon AP. Desmoplastic malignant melanoma: a systematic review. Br J Dermatol 2005;152: 673e8. 5. Quinn MJ, Crotty KA, Thompson JF, et al. Desmoplastic and desmoplastic neurotropic melanoma: experience with 280 patients. Cancer 1998;83:1128e35.
Jurga Pikturnaite Jill Webb Plastic Surgery and Burns, Queen Elizabeth Hospital, Mindelsohn Way, Birmingham, B15 2WB, UK E-mail address: [email protected] 13 June 2014
CORRESPONDENCE AND COMMUNICATION Desmoplastic melanoma in a fingertip: A rare entity* Dear Editor, Desmoplastic melanoma (DM) represents a rare variant of skin cancer that is often missed due to absence of any pigmentation and a confusing appearance histologically. It is particularly rare in a fingertip resulting in delayed treatment. We present a misdiagnosed case to raise awareness of DM wishing others to learn from our delays. Our 40 year old female patient was referred from a skin oncology clinic with a 3 year history of swelling on the dorso-ulnar side of the little finger, just proximal to the nail fold. For 2 years it had been intermittently ulcerating. There was no axillary lymphadenopathy. The referring diagnosis was of a mucous cyst (Figure 1), but the senior author disagreed. While uncertain of the diagnosis, differentials included nerve tumours and dermatitis artifacta. The initial MRI demonstrated a well defined extraarticular lesion for which surgical excision was planned. However at surgery no lesion was found, just an area of scarring, which was biopsied. Histology showed fibrotic changes and no malignancy. Even after multiple stains, no clearer diagnosis was forthcoming. At review with a colleague for second opinion, the diagnosis remained uncertain. Due to pain, flexion deformity and ulceration the patient chose to have an amputation. This was done through the middle phalanx, 9 months after original referral. Histology at this stage demonstrated a desmoplastic malignant melanoma with Breslow thickness of 4.5 mm, ulceration, invasion of bone marrow, extensive perineural invasion and incomplete excision at both soft tissue and bony margins. It was strongly Se100 positive, as was the first specimen when later tested. Definitive surgery required ray amputation, performed using Moh’s technique (Figure 2). Skin margins were still involved, therefore it was resected further; this was considered clear on Moh’s histology even though there were scattered cells still staining for Se100.
* This work was in part presented at the ESPRAS 2014, Edinburgh (e-poster) on the 9th July 2014.
DM represents a rare variant of skin malignancy. It is more common in men aged 60e70. Only a third of desmoplastic melanomata occur in upper extremities while exposed areas such as head and neck are affected more frequently (50% of cases).1e4 Due to their bland clinical appearance, only a third of all cases are initially identified as malignant melanoma.1 Up to 70% of desmoplastic melanomata have no visible pigmentation and clinically look like scars or other benign lesions. As a result, like in our case, an incisional rather than excisional tissue biopsy is performed with a tendency to miss the diagnostically most characteristic portion of the lesion and to misinterpret histology, which commonly resembles simple fibroblastic proliferation. In a fingertip this poses a particular challenge: misdiagnosis is common and delay in treatment means more aggressive surgical clearance which can leave the patient incapacitated. Microscopically DM is characterised by melanocytic hyperplasia with intense fibroblastic reaction and presence of spindle cells (melanocytes), which stain strongly for the Se100 protein antigen. The Se100 protein antigen is the most valuable marker to aid the diagnosis of DM.2,3 It exhibits a strong reaction in the actual lesion, but can still be found in the scar already cleared of melanoma.3 Confusingly the Se100 stain is also positive in schwannomata and other nerve tumours.3 Histological findings in our case included fibroblastic reaction but no melanocytic hyperplasia, so our first tissue diagnosis was misinterpreted as scar. It stained for the Se100 at the later histological examination, which helped to diagnose DM.
Figure 1 Pre-operative appearance of the lesion and resulting fingertip deformity.
http://dx.doi.org/10.1016/j.bjps.2014.09.040 1748-6815/ª 2014 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.
e46
Correspondence and communication
Ethical approval N/A.
Financial support No financial support received.
Conflict of interest No conflict of interest to declare.
Written consent Figure 2
Post-operative result.
As seen in our patient, more advanced disease at diagnosis means more aggressive and potentially more incapacitating treatment: the mean Breslow thickness at the time of diagnosis in DM is 2.0e6.5 mm3,4 with half of all lesions being thicker than 4 mm and with only 4% limited to Clark’s level IV.1 Local recurrence rates for a given Breslow’s depth are higher,3e5 but regional recurrence is less common.4,5 In addition, DM presents with neurotropism in up to 78%4 which makes this tumour more difficult to clear and more likely to recur locally.3 Regardless though, 5-year survival rates are relatively good (67e89%3). As with other melanomata, surgical excision is the treatment for DM, which in digits usually means amputation. Excision margins for DM are not established but advised to be wider than in most melanoma variants e at least 2 cm. Due to the rarity of DM, the role of sentinel node biopsy, radiation or any other adjuvant therapy has not yet been determined in desmoplastic variants.3 In summary, desmoplastic melanoma tends to be diagnosed late; in long-standing and thick lesions. Those involved in managing patients with skin disorders should be aware of this clinicopathological variant. This unusual and initially inconspicuous case of DM in a fingertip demonstrates the potential for misdiagnosis and the need for awareness of desmoplastic melanoma in a hand in order to manage it appropriately and in timely manner.
Patient has given written consent to use her clinical photographs for research and publication purposes.
References 1. de Almeida LS, Requena L, Ru ¨tten A, et al. Desmoplastic malignant melanoma: a clinicopathologic analysis of 113 cases. Am J Dermatopathol 2008 Jun;30(3):207e15. 2. Chung KC, Calkins ER, Crawford R, Rees RS. Desmoplastic melanoma of the hand: case reports and review of the literature. J Hand Surg Am 1995 Sep;20(5):873e6. 3. Chen LL, Jaimes N, Barker CA, Busam KJ, Marghoob AA. Desmoplastic melanoma: a review. J Am Acad Dermatol 2013 May; 68(5):825e33. 4. Lens MB, Newton-Bishop NJ, Boon AP. Desmoplastic malignant melanoma: a systematic review. Br J Dermatol 2005;152: 673e8. 5. Quinn MJ, Crotty KA, Thompson JF, et al. Desmoplastic and desmoplastic neurotropic melanoma: experience with 280 patients. Cancer 1998;83:1128e35.
Jurga Pikturnaite Jill Webb Plastic Surgery and Burns, Queen Elizabeth Hospital, Mindelsohn Way, Birmingham, B15 2WB, UK E-mail address: [email protected] 13 June 2014
