Solitary Fibrous Tumor of the Kidney

Definition

A rare mesenchymal tumor characterized by hemangiopericytomatous pattern

Clinical Features

• Incidence

  Intrarenal solitary fibrous tumor is a rare neoplasm.

• Age

  It usually arises in middle-aged adults.

• Sex

  There is no gender predominance.

• Site

  There is no site predilection.

• Treatment

  The complete surgical resection is the first choice of therapy if feasible.

• Outcome

  Intrarenal solitary fibrous tumor shows an indolent behavior. However, aggressive cases have been reported (Hsieh et al. 2011).

Macroscopy

Well-circumscribed solitary mass with white, firm cut surface

Microscopy

The histologic appearance is the same as the pleural tumor, characterized by spindle cells with bland nuclear feature without a specific pattern, thick bands of collagen, and prominent branching and hyalinized vessels (Fig. 1) (Kuroda et al. 2014; Wang et al. 2001).

Immunophenotype

The tumor is typically positive for CD34, STAT6 (Saeed et al. 2019), CD99, and BCL-2.

Molecular Features

NAB2-STAT6gene...