Papillary Adenoma

Definition

Papillary adenoma is unencapsulated tumor composed of cells with low ISUP/WHO grade arranged in papillary or tubular architecture and 15 mm in diameter or smaller (Umbreit and Thompson 2011). A diagnosis of papillary adenoma on needle biopsy should be made with extreme caution.

Clinical Features

• Incidence

  In autopsy series, papillary adenomas have been reported in approximately 10% of individuals (Caliò et al. 2019).

• Age

  The frequency of papillary adenomas increased throughout adulthood.

• Sex

  Papillary adenomas are roughly five times more frequent in men than in women.

• Site

  There is no site predilection.

• Treatment

  Papillary adenoma is a clinically silent and incidental finding; a therapeutic approach is not required.

• Outcome

  Papillary adenoma is a benign tumor.

Macroscopy

Papillary adenomas arise in the renal cortex and often are subcapsular.

Microscopy

Papillary adenoma shows a papillary, tubular, or tubulopapillary architecture (Fig. 1).

Fig. 1

A subcapsular papillary...