Interesting cases

Acinar adenocarcinoma GG2 + adenoid cystic (basal cell) carcinoma

Acinar adenocarcinoma GG2 + adenoid cystic (basal cell) carcinoma

Seven of 12 cores showed adenocarcinoma GG2 with cribriform morphology. These areas expressed PSA (strong and diffuse stain) and did not stain for keratin 7, p63, high molecular weight cytokeratin, BCL2. Five of the 12 cores exhibited adenoid cystic (basal cell) carcinoma. This neoplasm did not express PSA and stained for BCL2 (strong and diffuse pattern). Tumor cells were positive for keratin 7, p63, high molecular weight keratin. Keratin 7 highlighted foci of luminal differentiation. p63 and high molecular weight keratin stained basaloid cells in areas of solid growth and the periphery of nests showing dual population and luminal differentiation.

Patients with adenoid cystic (basal cell) carcinoma range from 42 to 93-years. These tumors are usually diagnosed in transurethral resection specimens. These tumors do not elevate PSA serum levels unless they occur with concomitant acinar adenocarcinoma, as observed in this case.

These tumors show different growth patterns include adenoid cystic / cribriform and solid nests with basaloid cytology. Differential diagnosis from florid basal cell hyperplasia is based on the following criteria: atypia, infiltrative growth, perineural invasion, necrosis (rare) and extraprostatic extension. Most tumors do not express PSA. Luminal cells stains for keratin 7 and basaloid cells are labelled by typical basal cell markers. Tumors cells show strong BCL2 expression and HER2 overexpression. MYB::NFIB fusion can be detected in 17–47% of prostatic adenoid cystic (basal cell) carcinomas. This rate is similar to that seen in their salivary gland counterparts.

These tumors commonly show aggressive behavior. Extraprostatic extension at radical are common (44–71%) and 14-29% of patients develop distant metastasis.

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Cozzi S, Bardoscia L, Najafi M, Botti A, Blandino G, Augugliaro M, Manicone M, Iori F, Giaccherini L, Sardaro A, Iotti C, Ciammella P. Adenoid Cystic Carcinoma/Basal Cell Carcinoma of the Prostate: Overview and Update on Rare Prostate Cancer Subtypes. Curr Oncol. 2022 Mar 9;29(3):1866-1876.

McKenney JK, Iczkowski KA, Parwani AV, van Leenders GJLH. In: WHO Classification of Tumours Editorial Board. Urinary and male genital tumours [Internet]. Lyon (France): International Agency for Research on Cancer; 2022 [cited YYYY Mmm D]. (WHO classification of tumours series, 5th ed.; vol. 8). Available from: https://tumourclassification.iarc.who.int/chapters/36.

Delyane de Azevedo Batista Santiago
Federal University of Bahia / Hospital Universitário Professor Edgard Santos
Salvador, Bahia, Brazil

Marcella Mello Aguiar
Federal University of Bahia / Hospital Universitário Professor Edgard Santos
Salvador, Bahia, Brazil

Daniel Athanazio
Imagepat, Laboratory of Pathology
Federal University of Bahia / Hospital Universitário Professor Edgard Santos
Salvador, Bahia, Brazil

Prostate

Prostate; Basal cell carcinoma; Adenoid cystic carcinoma; Differential Diagnosis