Pulmonary synovial sarcoma

Case contributed by A.Prof Frank Gaillard



Patient Data

Age: 20 years
Gender: Female

CXR demonstrates a very well circumscribed mass in the left upper zone. The differential is that of a solitary pulmonary mass. 

Case Discussion


Macroscopic description

A  lobectomy specimen, consistent with left upper lobe, 140  x 130 x 30mm, with attached bronchial remnant, 15mm in  diameter and 6mm  long.  In the middle  of the left upper lobe towards to the anterior  surface, is a relatively  well circumscribed, irregular, soft shiny and  tan tumour, 60 x 35 x  45mm.  It is 4mm from the pleural  surface.   The overlying  pleura  is smooth  and  glistening.  The  tumours appears to  be within 1mm of  the bronchus, but  does not appear to  invade through  it. It is  approximately 5mm  from the  bronchial resection margin.   Elsewhere,  the lung  parenchyma  is variegated  brown  tan, with patchy,  pale regions,  more  prominent  towards  the  superior  aspect and anterior inferior  aspect.

Microscopic description

Sections  from the   macroscopically   described  lesion  show  a well circumscribed, highly  cellular neoplasm composed  of interlacing fascicles  of plump spindled  cells  separated by small  or ectatic  thin-walled blood  vessels.   The tumour  cells  possess  overlapping,  large,  elongate ovoid  nuclei with multiple small nucleoli, and frequent mitotic figures are noted  (21/10hpf).   There  are large  areas  of  necrosis.   There are  also less cellular, oedematous  foci scattered  throughout.  In  areas, tumour bulges into an bronchioles,  undermining epithelium,  but there is no cystic component.  No  lymphovascular  space invasion  is seen, and  the lesion is clear of  the  pleural  surface.   No  rhabdomyosarcomatous   or  chondroid differentiation is  seen. Immunohistochemical  stains  have been performed, and the tumour  cells show  diffuse  immunoreactivity  for  vimentin, CD99, bcl-2 and CD56.   There is focal  immunoreactivity for  calretinin and weak and patchy  immunoreactivity for  epithelial membrane  antigen.  The tumour cells are negative  for cytokeratins  (AE1/AE3, cytokeratin  7, cytokeratin 5/6),  S100   protein,   gp-100,  desmin,   smooth   muscle   actin,  CD34, synaptophysin and TTF-1.  Overall, the features  are most in keeping with a  monophasic    pulmonary   synovial  sarcoma.   

FISH studies were POSITIVE  for SYT (18q11.2)  breakapart rearrangement in >50% of cells  examined which  is consistent  with a diagnosis  of synovial sarcoma. The accuracy of these results is dependent on the correct identification of tumour on the sections  provided, and the assumption  that positive results will be identified by a large proportion  of cells within the tumour having a rearrangement.

Final diagnosis 

Malignant  spindle  cell  tumour with features favouring  monophasic pulmonary  synovial sarcoma,  60 mm diameter,  clear of margins, with no lymph node  metastases identified.  

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Case information

rID: 12117
Published: 22nd Oct 2010
Last edited: 16th Jul 2018
System: Chest
Tag: cxr
Inclusion in quiz mode: Included

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