Pulmonary malignant melanoma with distant metastasis assessed by positron emission tomography-computed tomography

Pulmonary metastatic melanoma: current state of diagnostic imaging and treatments

Melanoma is the deadliest form of skin cancer with an estimated incidence of over 160,000 cases annually and about 41,000 melanoma-related deaths per year worldwide. Malignant melanoma (MM) primarily occurs in the skin but has been described in other organs. Although the respiratory system is generally afflicted by tumors such as lung cancer, it is also rarely affected by primary MM. The estimated incidence of pulmonary MM of the lung accounts for 0.01% of all primary lung tumors. The current understanding of pulmonary MM of the lung pathophysiology and its management are not well established. We aim to survey current clinical modalities with a focus on diagnostic imaging and therapeutic intervention to guide providers in the management of patients with a high index of suspicion.

Lung-only melanoma: UV mutational signature supports origin from occult cutaneous primaries and argues against the concept of primary pulmonary melanoma

Primary pulmonary melanoma (PPM) is an entity recognized by the thoracic WHO classification. However, given the absence of native melanocytes in the lung and the known phenomenon of regression of cutaneous melanomas, the existence of PPM has remained controversial. Herein we investigate clinicopathologic and genomic features of lung-only melanomas with the goal to clarify their site of origin. We identified 10 melanomas involving exclusively lung with no current or previous cutaneous, uveal, or mucosal primaries. Four patients had solitary lesions with mean size of 5.1 cm (range 3.0-10.1 cm), meeting the criteria of PPM. Four patients had 2-3 lesions and 2 patients had >10 lesions. All cases underwent targeted next-generation sequencing interrogating up to 468 cancer genes, which revealed mean tumor mutation burden of 42.6 per megabase (range 1.8 to 126) and frequent mutations involving BRAF, NRAS, NF1, KIT, and KRAS - a genomic profile typical of UV-associated cutaneous melanoma. Mutational signature was assessable for eight cases harboring >20 mutations. This revealed that all evaluable cases harbored a dominant UV signature. In addition, one nonevaluable case harbored a GG > AA TERT promoter variant that is highly specific for UV-mutagenesis. As control groups, using the same methodology, a dominant UV signature was identified in 97% (470/486) of cutaneous melanomas, whereas no lung adenocarcinoma (n = 291) exhibited this signature. Notably, the clinical and pathologic features of solitary melanomas, especially those with large size and epithelioid morphology, closely mimicked primary lung carcinomas, highlighting a major potential for misdiagnosis. In conclusion, presence of a UV signature provides direct evidence that nearly all lung-only melanomas in this series, including solitary lesions meeting the strict criteria of PPM, represent metastases from occult cutaneous melanomas. This suggests that lung-only melanomas should be considered as likely metastatic even in the absence of a known primary melanoma elsewhere.

Primary Melanoma of the Lung: A Systematic Review

Background and Objectives: The respiratory apparatus, generally affected by highly aggressive tumors like lung cancer and mesothelioma, is rarely affected by primary malignant melanoma. The aim of this review was to identify cases of primary malignant melanoma of the lung (PMML) published in the modern scientific literature, and to describe their main clinical, pathological and therapeutic features. Materials and Methods: A systematic search of publications in the electronic database PubMed has been performed using keywords, and the references of the selected articles were checked to identify additional missing studies. Results: Globally 52 papers reporting on 76 cases were identified. Among them there were 47 reports of a single case, three papers reporting on two cases each, and two larger case series published in 1997 and 2005 including eight and 15 cases, respectively. Conclusions: PMML was generally diagnosed in middle-aged males, without any apparent correlation with cigarette smoking. It was more frequently found in the lower lobes and the left lung. The tumors were generally pigmented, composed by epithelial and/or spindle cells with large nuclei and prominent nucleoli, nuclear atypia, and numerous mitotic figures; they commonly showed immunostaining for S-100, HMB 45 and Melan-A. Early detection and surgical resection were the main determinants of survival from this rare malignancy.

Primary Pulmonary Malignant Melanoma Found While Evaluating New Onset Cough: A Case Presentation and Literature Review

Malignant melanoma is a nonepithelial neoplasm of melanocytes. It is tremendously rare for this condition to primarily involve the respiratory tract, accounting only for 0.01% of the lung malignancies. It often presents as a solitary nodule provoking mass effect and/or obstructive symptom. It most commonly affects patients 50 years old and older, with no gender predilection. Complete surgical excision is the treatment of choice; nevertheless, chemotherapy or radiation might be necessary depending on tumor location and/or metastasis status. Recently, biochemotherapy and immunotherapy have emerged as promising treatment modalities. We present a case of Primary Pulmonary Malignant Melanoma (PPMM) in a 76-year-old male with no previous personal or family history of cancer who presented with new onset nonproductive cough. We also present an analysis with high yield points summarizing clinical features, diagnostic workup, and management of PPMM. Finally, we post a table summarizing all the cases ever reported in English literature.

Primary Pulmonary Malignant Melanoma: Report of an Important Entity and Literature Review

Malignant melanoma involving the respiratory tract is nearly always metastatic in origin, and primary tumors are extremely rare. Published data on primary pulmonary malignant melanomas are limited. Up to now 40 relevant cases have been reported in the English literature. Herein, we report a case of a 56-year-old female patient who presented with intracranial metastases due to primary pulmonary melanoma. She underwent bronchoscopy and died 5 months after the initial diagnosis despite the administered biochemotherapy and subsequent immunotherapy. To establish the diagnosis of primary pulmonary malignant melanoma, any extrapulmonary origin was excluded by detailed examination and radiographic imaging. Moreover, an extensive review of the literature regarding this rare entity has been performed.