Intramammary metastatic melanoma of unknown primary origin in a 58-year old patient: a case report

Is primary breast melanoma a true pathological entity? The argument against it

Background

Previous studies have reported cases of primary melanoma of the breast parenchyma (PMBP), but the pathogenesis of this disease remains poorly understood. We review the presentation and outcomes of reported cases and provide detailed pathological analysis of four additional cases. Furthermore, we discuss potential theories regarding the pathogenesis of this clinical presentation.

Results

We identified 29 published studies (n = 95 patients) and report four new cases (n = 99). Ninety-one (92 %) patients were female, with a median age of 50 years. Previous skin melanomas were reported by 56 % of patients, with the trunk being the most common location (32.7 %) followed by the upper extremities (20 %). The most common tumor location reported (n = 73) was the right (49 %) upper outer quadrant (56 %). The median time from skin melanoma diagnosis to the presence of a breast mass was 65 months (1-192). Nodal status at presentation was reported in n = 67 (68 %) patients. Of these, positive nodal metastases were seen in 40.3 %, while distant metastatic disease at presentation was reported in 30 % of patients. Surgery was performed in 66 %, being partial mastectomy (PM) the most common procedure in 82 %. Adjuvant therapy was described in 38 patients. The reported (n = 12) median survival was 11.5 (1-70) months.

Conclusion

Melanomas identified in the breast parenchyma are likely the result of nodal or hematogenous spread from previously known or unknown melanomas, and should not be considered as PMBP. Management should be multidisciplinary, including surgical excision aimed at obtaining negative margins with lymphadenectomy of clinically positive nodes and neoadjuvant/adjuvant immunotherapy.

Melanoma of Unknown Primary With Metastasis to the Brain: A Case Report and Review of the Literature

We present the case of a 72-year-old male found to have melanoma of unknown primary (MUP) in the lung with brain metastasis. The patient has a history of prostate cancer with radical proctectomy in 1999, hypertension with right-sided heart failure, and bilateral cataracts treated operatively. He presented to their home hospital after an unwitnessed fall, with a history of left-sided weakness. He was found to have a parietal lobe mass and two lung masses, where he was transferred to our hospital for a higher level of care. Biopsy of the lung lesion revealed melanoma, and the patient did not have any skin or mucosal foci present to indicate a primary source. We present this case in conjunction with a review of the literature. Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, our review resulted in 31 MUP case reports. Data was extracted on epidemiology, clinical presentations, diagnostics, treatment, and outcomes. The mean age was 57.5 with a male-to-female ratio of 1:1.3. The greatest instances of MUP occurred in prior smokers and patients with comorbidities, accounting for 17.95% of cases each. Thirty-one percent of patients presented with a growing palpable mass, 21% with gastrointestinal symptoms, and 21% with B-symptoms. Biopsy was the diagnostic standard, and the majority of patients also underwent biomarker studies. Treatment varied widely, and many patients underwent multiple phases. Outcomes ranged from death within several months to a disease-free period of three years. Our paper highlights the complexity and nuances of diagnosing MUP and primary malignant melanoma of the lung (PMML) and calls for further investigations to improve diagnostic and therapeutic approaches for rare presentations of melanoma. Despite limitations in sample size and data heterogeneity, this study highlights the diverse presentation and disease course of MUP, necessitating further studies to optimize patient outcomes.

Malignant melanoma of the breast: controversies in the diagnosis and therapeutic management of a rare nosologic entity

Melanoma of the breast is an infrequent entity, presenting as either primary or metastatic from extramammary solid neoplasms. Depending on the involvement of the skin, primary malignant melanoma of the breast (PMMB) can be classified as cutaneous or noncutaneous. Cutaneous PMMB accounts for <5% of all melanomas and only 0.5% of all breast cancers. Furthermore, despite the rarity of metastatic breast neoplasms, melanoma comprises a frequent source of metastases. Metastatic potential of melanoma is associated with poor prognosis, and the majority of patients present more than one metastatic foci at the time of diagnosis. Diagnostic approach for both primary and metastatic melanomas of the breast is substantiated by fine needle aspiration (FNA) cytology along with immunohistochemistry. Nevertheless, verification of a metastatic mammary melanoma requires the discovery of a primary lesion. The mainstay of treatment for primary tumors is surgery, with radical local excision and axillary lymph node dissection or, on occasion, axillary sentinel node resection, while for metastatic tumors it depends on the specificities of the melanoma. Adjuvant therapy is always implemented. The aim of this survey is to meticulously review the literature of primary and metastatic malignant melanomas of the breast and report epidemiologic and clinicopathologic data for this rare entity. Clinical features, histogenesis, morphological, and immunochemical findings are discussed, while the role of current diagnostic and therapeutic management of this uncommon entity is emphasized.