Diffuse microscopic intransit metastases from malignant melanoma of the breast.

Sir: Intransit metastases are located between primary lesions of melanoma and the regional lymphatic drainage basin. Although they can occur in deeper lymphatics, intransit metastases are usually observed as subcutaneous or intracutaneous metastases. They probably originate from cells trapped in lymphatic channels.1–4 We report two cases with multiple simultaneous intransit metastases on the breast skin and tissue, treated by wide local excision including mastectomy, with review of the literature. A 27-year-old man with stage III malignant melanoma who had previously undergone wide local excision and axillary dissection was observed to have multiple intransit metastases on the left areola, confirmed histopathologically. No palpable mass was found on the breast (Fig. 1, left), and simple mastectomy was performed 17 months postoperatively. Examination of the specimen revealed the number of melanoma metastases within the lymphatic vessels and intransit metastases on the nipple-areola complex. Two intransit metastases that had developed on the proximal mastectomy flap in the space of 1 year were excised. The patient died of distant metastases and had no intransit metastases on the chest wall. A 35-year-old woman with stage III malignant melanoma had had a previous operation on the medial back and bilateral axillary lymph node basins in October of 1997. In January of 1999, histopathologic examination revealed light blue spots that were confirmed as intransit metastases on the right thoracic region between the posterior axillary line and the areola. Physically and radiologically, the breast was normal (Fig. 1, right). A simple mastectomy was performed and the defect was covered by a split-thickness skin graft. Histopathologic examination also revealed diffuse lymphatic infiltration in breast tissue, skin, and areola and also revealed intramammary lymph node metastases. Seven months postoperatively, the patient had no evidence of intransit or distant metastases. Both patients received adjuvant radiation therapy to the chest wall and chemotherapy. Because of the high risk of systemic micrometastases, the treatment of intransit metastasis is still a challenging problem, especially if they are localized on the trunk or the head and neck region. There are few reports about intransit metastases of truncal melanoma. In a report by Karakousis et al.,2 lesions were localized on the trunk in 17 of 52 patients. They recommended aggressive local treatment. Surgical excision of multiple lesions may prevent recurrence. Despite aggressive local treatment being the best approach, mastectomy seems to be extensive surgery, especially in the patients without breast mass or mammographic abnormality. The decision to perform a mastectomy was not difficult in our first case, because the patient was male and the intransit metastases were localized on the nipple-areola complex. This was not the case in the second patient, because both physical and mammographic examinations revealed no abnormality. The patient had only multiple light blue spots on the breast skin. Based on the first patient’s experience, mastectomy was recommended.