Primary pulmonary synovial sarcoma with calcification: A case report

Figures

• 

  Figure 1. Diagnostic imaging. (a) Computed tomography (CT) with a lung window setting indicated the presence of a well‐defined solid nodule in the right lower lobe. (b) Noncontrast CT with a mediastinal window setting showed punctate calcification in the eccentric part of the nodule. (c) Contrast‐enhanced CT revealed a strong contrast enhancement of 50 Hounsfield units in the nodule.

• 

  Figure 2. Macroscopic findings. The cut surface of the resected specimen showed a yellowish‐brown tumor with yellow‐whitish areas, measuring 1.8 cm in the largest diameter. The tumor was present entirely within the lung.

• 

  Figure 3. Histological findings using hematoxylin and eosin staining. (a) Spindle tumor cells are densely proliferating in interlacing fascicles with a herring‐bone pattern. (b) The tumor contained strands of ropy and wiry collagen, and bands of hyalinized collagen, corresponding to the yellow‐whitish areas on the cut surface (Fig. 2). (c) Foci of calcifications contiguous to the hyalinized collagen are shown. (d) Two mitoses of tumor cells are observed (arrow).

• 

  Figure 4. Gene analysis. (a) Fluorescence in situ hybridization analysis using formalin‐fixed, paraffin embedded tissues. A break‐apart signal with separate red and green signals revealed an SS18 rearrangement, whereas two fused yellow signals did not demonstrate an SS18 rearrangement. Almost all tumor cells revealed a SS18 break‐apart signal, indicating a chromosomal translocation of the SS18 gene. (b) Reverse transcription‐polymerase chain reaction analysis for the SYT‐SSX fusion gene. The SYT‐SSX2 gene (109 bp) was amplified; however, the SSX1 (151 bp) was negative. The housekeeping gene phosphoglycerokinase 1 (PGK 1: 100 bp), used as a positive control, was also amplified. (c) Sequencing analysis of the SYT‐SSX gene transcripts. A vertical line indicates the fusion site of the SYT and SSX2 genes.