A SMALL AMELANOTIC NODULE ON THE FRONT
Josep Malvehy, A. Barreiro
Hospital Clinic of Barcelona, Spain
Case presentation: a 72-year-old woman with previous cutaneous melanoma on the left leg 20 years ago (stage IIA), familial melanoma syndrome and carrier of a mutation in CDKN2A. In one of the follow visits she presented with two small amelanotic lesions in the front (4 and 2 millimetres in diameter) (Figure A). The patient was not aware of changes in the lesions.
Diagnostic work up, treatment and follow up
Dermoscopy showed in the larger lesion a asymmetric pink and bluish coloration with atypical polymorphous vessels (figure B). The other small lesion showed an unspecific pattern and polymorphous vessels (Figure C).
With the clinical diagnosis of nodular melanoma and melanoma skin metastasis, both lesions were excised. Histopathology confirmed a non-ulcerated nodular melanoma with Breslow thickness of 1,2 mm with no mitosis, BRAF wild type (Figures D-G).
The small lesion corresponded to dermal metastasis (Figure H). Blood tests, brain MRI and CT scan of the neck, thorax and abdomen were normal. With these results a melanoma stage IIIB (T2, N2c, M0) was concluded (AJCC 2010).
Wide excision of the two lesions with one centimetre of margin and advancement flap was performed. After 6 weeks of the surgery the tumour relapsed with multiple small skin metastases on the frontal face and scalp in 3 centimetres around the surgical scar. The patient was treated topically with imiquimod (daily during 4 wks and 5 times weekly once the treated site had become intolerably erythematous and inflamed) with complete clinical response. Follow-up with physical examination, digital dermoscopy with photographic documentation of the skin, blood tests and sonography of the neck (every 3 months) and brain MRI and thorax and abdomen CT scanners (every 6 months) were normal during two years. In one of the visits the patient presented a new brown pigmented lesion (2,5 millimetres) resembling a dermal nevus on the frontal scalp at 2 centimetres of the primary tumour (Figure I). Dermoscopy showed a nevoid brown globular pattern (Figure J). The lesion was excised and histopathology showed a small skin metastasis. The patient was treated again with imiquimod of the area with the same schedule. At the moment after 6 weeks no new lesions have appeared.
- Fast growing melanomas may mimic benign lesions at the initial stage.
- Atypical vessels in dermoscopy are diagnostic clues in hypo-pigmented melanoma. Skin metastasis have different patterns and they may mimic clinically and dermoscopically benign lesions including dermal or blue melanocytic nevi or angiomas.
- Physical examination and dermoscopy with photographic documentation of the skin is essential to rule out skin metastasis.
- Topical imiquimod either in monotherapy or in combination with cryosurgery, retinoids or other immunotherapies can be useful to treat multiple small melanoma skin metastases in selected patients.
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