Primary Mesenchymal Chondrosarcoma of the Mediastinum with Adrenal Metastasis

A Rare Scenario

Abstract

Mesenchymal chondrosarcoma (MC) is a rare malignant tumor that represents <3% of all chondrosarcomas. Herein, we describe extraskeletal MC involving the mediastinum in a 24-year-old gentleman with a rare phenomenon of adrenal metastasis.

A 24-year-old male complained of breathlessness, disturbed sleep, weight loss, and loss of appetite of 1-month duration. A contrast-enhanced computed tomography (CT) scan of the chest revealed a large mass in the mediastinum with calcific changes and filling defects in the superior vena cava and right atrium. A CT-guided biopsy from the mediastinal mass was done. H and E-stained photomicrographs show atypical cartilaginous tumor mixed with a mesenchymal area of malignant round cells [Figure 1h and i]. Immunohistochemistry showed positive nuclear staining with S-100 protein in atypical cartilage [Figure 1j] and membranous positivity of CD99 in mesenchymal cells [Figure 1k], consistent with mesenchymal chondrosarcoma (MC).

Figure 1: F^18-2-fluoro-2-deoxy-glucose (FDG) positron-emission tomography/computed tomography showed a large mediastinal soft tissue mass (a-g, white arrows) with extensive calcifications and increased peripheral FDG uptake. An FDG -avid soft tissue mass was noted in the right suprarenal region (a-g, blue arrows), also showing central calcification (d). H and E-stained photomicrographs show atypical cartilaginous tumor mixed with mesenchymal area of malignant round cells (h-i). Immunohistochemistry showed positive nuclear staining with S-100 protein in atypical cartilage (j) and m. Membranous positivity for CD99 in mesenchymal cells (k)

F^18-2-fluoro-2-deoxy-glucose (FDG) positron-emission tomography with CT (PET/CT) for staging was done. FDG PET/CT showed a large mediastinal soft tissue mass [Figure 1a-g, white arrows] measuring 14.3 cm × 17 cm with extensive calcifications and increased peripheral FDG uptake with a maximum standard uptake value (SUVmax) of 8.57. An FDG avid soft tissue mass was noted in the right suprarenal region [Figure 1a-g, blue arrows], also showing central calcification [Figure 1d], measuring 3.5 cm × 3.2 cm with SUVmax of 7.64. The right adrenal gland was not visualized separately.

MC is a rare malignant tumor that represents <3% of all chondrosarcomas.[¹] Reports of metastasis of MC to unusual sites such as adrenal, pancreas, and thyroid are few in the published literature.[^2,3,4,5] Detection of adrenal metastasis on PET/CT in case of extraskeletal MC is however not reported. Histopathologic evidence of the adrenal metastasis was not achievable as the patient was lost to follow-up; however, the imaging features suggest this possibility given the overall scenario.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient has given his consent for his images and other clinical information to be reported in the journal. The patient understands that name and initials will not be published and due efforts will be made to conceal identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.