Background

A 27-year-old male presented with history of progressive shortness of breath since 2 years and noisy respiration since 1 month.  CECT chest showed an ill defined heterogeneously enhancing soft tissue lesion in the pre-carinal location with small polypoidal endoluminal soft tissue component projecting into the lower trachea causing partial airway narrowing. Excision biopsy sent for examination.

Microscopy

Fig.8a; H&E; 0.65x

Fig.8b; H&E; 2.5x

Fig.8c; H&E; 5x

Fig.8d; H&E; 20x

Fig.8e; H&E; 5x

Fig.8f; H&E; 10x

Images show a tumor in predominantly cribriform pattern lined by inner luminal and outer myoepithelial cells with punched out hyalinized or myxoid globules [Fig.8a-d]. The tumor infiltrates the tracheal cartilage [Fig.8e] and overlying respiratory mucosa [Fig.8f].

Final Impression: Adenoid Cystic Carcinoma- Grade 2.

POINTS TO REMEMBER

• Salivary gland tumor composed of bilayered epithelial and myoepithelial neoplastic cells arranged in cribriform, tubular or solid pattern
• Mean age of presentation: 45 years
• Sites of involvement:
  • Minor salivary glands > major salivary glands
  • Most common: oral cavity
  • Other sites: sinonasal tract, nasopharynx, oropharynx, trachea
  • Amongst major salivary glands: Parotid is the most common site
  • Most common site of metastases: Lung parenchyma
• Prognostic factors:
  • Stage
  • Margin status
  • High mitotic index
  • Solid architecture
• Genetic alteration: Fusion involving MYB, MYBL1 and NFIB genes is characteristic and diagnostic
• Treatment:
  • Complete surgical resection with adequate margins with adjuvant radiotherapy.
  • Chemotherapy in case of metastases
• Immunohistochemistry: Positive Stains:
  • Ductal component: CK7 & CD117
  • Myoepithelial component: p63, p40, Calponin, S100, SMA & CK
• Differential diagnosis:
  • Epithelial myoepithelial carcinoma (cribriform pattern is focal, if present, papillocystic architecture, clear myoepithelial cells, no angulation of nucleus & HRAS mutation)
  • Basal cell adenocarcinoma (shows peripheral palisading)
  • Polymorphous adenocarcinoma (usually shows one type of tumor cells)

Contributed by: Dr. Meenakshi Kamboj

Compiled by: Dr. Ankur Kumar & Dr. Himanshi Diwan

In case of queries, email us at: kumar.ankur@rgcirc.org

Adenoid cystic carcinoma Head & Neck Trachea

Last modified: 05/06/2021