J Korean Soc Radiol.  2013 Mar;68(3):213-216. 10.3348/jksr.2013.68.3.213.

Malignant Melanoma Presenting as Superior Mediastinal Mass without Extrathoracic Primary Melanoma

• You MW
• Sung DW
• Lee YK

• KMID: 1748453
• DOI: http://doi.org/10.3348/jksr.2013.68.3.213

Abstract

Malignant melanoma most commonly occurs in the skin, and other organs are secondarily involved. Malignant melanoma presenting in the mediastinum without an extrathoracic primary is very rare. Authors report a case of malignant melanoma of the superior mediastinum without clinical history of extrathoracic malignant melanoma primarily and discuss its radiologic findings. CT shows lobulated heterogenous enhanced mass. Magnetic resonance shows mild hyperintense mass on T1 and T2-weighted images contained focal hemorrhage and necrosis, and invasion to neural foramen. In addition, positron emission tomography/computed tomography shows high standard uptake values uptake of the mass.

MeSH Terms

Electrons
Hemorrhage
Magnetic Resonance Imaging
Magnetic Resonance Spectroscopy
Mediastinal Neoplasms
Mediastinum
Melanoma
Necrosis
Skin

Figure

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  Fig. 1 Imaging findings of superior mediastinal mass in a 32-year-old man. A. Chest radiography shows lobulated contour of mass on the right lung apex with left side deviation of trachea. The lesion shows homogenous opacity, obtuse angle with adjacent pleura and smooth interface with right upper lung. Cervicothoracic sign is positive (mass opacity above the clavicle), so the lesion would be located in the posterior portion of superior mediastinum. B. Chest CT shows well margined lobulated and homogenously enhanced mass on right superior mediastinum. Right tracheoesophageal groove is obliterated, left side tracheal deviation and compression or invasion of great vessels (right common carotid, subclavian arteries and internal jugular vein). Some calcifications are visible on the mass. C. Axial T2-weighted MR image at the upper T2 level (a), shows heterogenous mass (arrows) with intermediate to high signal intensity (compared with adjacent muscles). (b) The mass lesion has also slightly hyperintense area on sagittal T1-weighted image. Invasion of T1-2 and T2-3 neural foramina is noted (arrow). Higher signal intensity area at the lower portion of the mass (arrowhead) correlated with the calcifications on the CT scan. (c) Contrast enhanced T1-weighted MR image with fat suppression shows heterogeneous enhancement of mass. D. (a, b) Positron emission tomography/computed tomography shows high intense signal (standard uptake values 8.25) at right apex, and not uptake at the portion of necrotic area. E. The gross pathologic examination reveals a dark brownish lobulating mass. Multiple tan-brown areas of soft to firm tissues with areas of hemorrhage and necrosis are noted at the cut-section of the mass. F. The histologic specimen shows large pleomorphic cells with prominent nucleoli with some of which contain melanin pigments (H&E, × 200).

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