Abstract
Background Primary lung sarcoma (PLS) differs in management protocols and prognosis from the
more common primary lung carcinoma (PLC). It becomes imperative to raise a high index
of suspicion on radiological and pathological features.
Purpose The aim of this study is to highlight the variable imaging appearances of PLS compared
with PLC, which impacts radiologic - pathologic correlation.
Materials and Methods A retrospective observational study of 68 patients with biopsy-proven lung tumors
who underwent baseline imaging at our tertiary care cancer hospital was conducted
between January 2018 and March 2022. The patient details and imaging parameters of
the mass on contrast-enhanced computed tomography (CECT) were recorded and analyzed
for patients with PLS and compared with PLC. Follow-up imaging was available in 9/12
PLS and 52/56 PLC patients.
Results Among 12 patients with PLS, 5 patients had synovial sarcoma on histopathology. PLS
was seen in patients with a mean age of 40.8 years; the mass showed a mean size of
13.2 cm, lower lobe (75%), parahilar (75%), hilar involvement (41.7%), oval shape
(41.7%), circumscribed (25%) or lobulated (75%) margins, lower mean postcontrast attenuation
of 57.3 HU, fissural extension (50%), calcification (50%), and no organ metastasis
other than to the lung. PLC (56 patients) was seen in the elderly with a mean age
of 54.8 years; the mass showed a mean size of 5.7 cm, irregular shape (83.9%), spiculated
margins (73.2%), higher mean postcontrast attenuation (77.3 HU), chest wall infiltration
(30.4%), and distant metastasis (58.9%) at baseline imaging. A statistically significant
difference (p < 0.05) was seen between sarcoma and carcinoma in the mean age, size, site, shape,
margins, postcontrast attenuation, presence of calcifications, fissural extension,
and distant metastasis.
Conclusion The distinct imaging features of sarcoma help in differentiating it from carcinoma.
This can also be used to corroborate with histopathology to achieve concordance and
guide clinicians on further approach.
Keywords
lung neoplasms - carcinoma - sarcoma - synovial sarcoma - SYT–SSX fusion protein
