Luna Li, MD, PhD, Wafaa A. Elatre, MD, MPH
History
– 59 year old male with medical history of diabetes mellitus, hypertension, heart failure with reduced ejection fraction, and possible malignancy.
Patient found to have pleural effusion as well as possible mass in bronchus and diffuse lymphadenopathy in mediastinum.
Had diagnostic thoracentesis on 10/28/22. Diagnosis “positive for carcinoma” with unknown origin on cytology
Immunoreactivity for GATA3, CK7 and mammaglobin are in favor of a breast primary, while a urothelial cell origin cannot be entirely ruled out.
Biopsy of right bronchus intermedius mass on 11/1/2022 was performed. Pathology diagnosis was well-differentiated squamous carcinoma with an atypical immuophenotype. The cells express GATA-3 which is a marker or urothelium.
• Patient developed pericardial effusion one month later. Patient also reports cough productive of white sputum, bilateral extremities swelling x1 week, and 20 lb weight loss over 1 month with decreased appetite. His shortness of breath is aggravated by ambulation. Patient has worked in construction for many years.
•Immunohistochemical staining were performed on the cell block to further characterize the lesion. CK7, GATA3, BRST-2, and Androgen Receptor were positive on tumor cells, CK5/6 and p16 were focally positive, while CK20, Mammaglobin, S100, SOX10, Uroplakin II, Calretinin, TTF-1 and Napsin A showed negative staining on tumor cells. Special staining for Mucicarmine was essentially negative.
Molecular testing
•Tempus Labs xT 648 gene panel performed on surgical biopsy specimen Right bronchus intermedius mass.
•xT 648 gene panel focused on actionable mutations by DNA sequencing.
•PIK3CA mutation p.I102_P104delinsKS with an inframe deletion – GOF (exon 1) was identified.
Discussion
•Primary pulmonary salivary gland–type cancer is rare and comprises less than 1% of all lung tumors.
•This group of tumors derives from small salivary glands in the respiratory system and mainly include two common histological subtypes of mucoepidermoid carcinoma and adenoid cystic carcinoma.
• Like salivary duct carcinoma, pulmonary salivary gland–type carcinoma is positive for androgen receptor (AR), GATA 3 is usually positive, and most cases are also positive for GCDFP-15 (BRST-2).
•HER2/neu expression is usually seen but diffuse strong membranous staining or HER2 amplification on FISH is seen in only 25% of cases.
A novel mutation in a pulmonary salivary-type duct carcinoma with a PIK3CA mutation was identified which could guide treatment options for this rare cancer