Sarcomas and Related Proliferative Lesions of Specialized Prostatic Stroma

Abstract

Sarcomas and related proliferative lesions of the specialized prostatic stroma have been the subject of case reports and, thus, have not been well characterized. We reviewed the clinicopathologic features of 22 cases and studied the immunohistochemical profile of 9. Patient age ranged from 25 to 86 years; mean age was 54 years, and peak incidence was in the 6th and 7th decades. The most common clinical presentation was urinary retention, then abnormal results of digital rectal examination, hematuria or hematospermia, and a palpable rectal mass. The cases were grouped into two categories: prostatic stromal proliferation of uncertain malignant potential (PSPUMP, 18 cases) and prostatic stromal sarcoma (PSS, 4 cases) based on the degree of stromal cellularity and the presence of mitotic figures, necrosis, and stromal overgrowth. Four histologic patterns of PSPUMP were identified: (1) hypercellular stroma with scattered cytologically atypical cells associated with benign glands, (2) hypercellular stroma with minimal cytological atypia associated with benign glands, (3) hypercellular stroma with or without cytologically atypical cells, associated with benign glands in a "leaflike" growth pattern that resembled phyllodes tumors of the mammary gland, and (4) hypercellular stroma without cytologically atypical stromal cells and without glands. Prostatic stromal sarcoma showed greater cellularity, mitoses, necrosis, and stromal overgrowth than PSPUMP and consisted either of stromal elements with benign glands in a pattern that resembled malignant phyllodes tumors of the mammary gland (3 cases) or of purely stromal elements (1 case). Positive immunohistochemical reactions were noted using vimentin in 9 of 9 cases, CD34 in 8 of 8, HHF-35 in 2 of 8, smooth muscle actin in 3 of 9, desmin in 4 of 8, S-100 protein in 0 of 9, estrogen receptor in 1 of 7, and progesterone receptor in 6 of 7. None of the cases classified as PSS were positive for HHF-35, smooth muscle actin, or desmin. Of the 13 patients classified as having PSPUMP who did not undergo definitive local therapy at the time of diagnosis, recurrent signs or symptoms were seen in six (46%), necessitating additional therapy. Distant metastases to lung and bone developed in one patient classified as having PSS. Clinical and pathologic findings in this patient suggested a progression from PSPUMP to PSS. We conclude that sarcomas and related proliferative lesions of the specialized prostatic stroma encompass a spectrum of histologic features and may be grouped into two clinicopathologic categories: PSPUMP and PSS. Based on their distinctive histologic appearance and immunohistochemical profile, PSPUMP and PSS can be differentiated from other mesenchymal lesions of the prostate.

Spindle cell lesions of the adult prostate

“…1 To date, three studies have examined large patient populations in order to address the pathologic and clinical features associated with these lesions. [2][3][4] Although STUMPs have been generally considered to variably represent either a hyperplastic or benign neoplastic stromal process, a subset of STUMPs has been associated with stromal sarcoma on concurrent biopsy material or has demonstrated stromal sarcoma on repeat biopsy, suggesting a malignant progression in at least some cases. [2][3][4] In general, patients with a diagnosis of STUMP have a good prognosis, as most cases are confined to the prostate and rarely progress to sarcoma.…”

“…[2][3][4] Patients presented most commonly with urinary obstruction, followed by abnormal rectal examination, hematuria, hematospermia, rectal fullness, palpable rectal mass or elevated serum prostate specific antigen (PSA) levels. On gross examination, STUMPs appear white-tan and may demonstrate a solid or solid-cystic pattern with smooth-walled cysts filled with bloody, mucinous or clear fluid.…”

Prostatic Stromal Tumor of Uncertain Malignant Potential (STUMP) Presenting with Multiple Lung Metastasis

“…Prostatic STUMP usually presents in the sixth and seventh decade of life 1 . The common clinical manifestations are lower urinary tract symptoms, abnormal digital rectal exam, hematuria, and rectal dysfunction.…”

“…Gaudin et al 1 grouped these tumors into two categories: prostatic stromal tumor of uncertain malignant potential (STUMP) and prostatic stromal sarcomas (PSS), based on the degree of hypercellularity, the presence of mitotic figures, necrosis, and stromal overgrowth. The neoplastic nature of prostatic STUMP remains controversial as the incidence is relatively rare and results of long term follow-up have not been established.…”

“…The neoplastic nature of prostatic STUMP remains controversial as the incidence is relatively rare and results of long term follow-up have not been established. However, there have been a few reports of high recurrence, spreading to contiguous organs, and metastasis [1][2][3][4][5][6][7][8] . We describe a case of prostatic STUMP, presenting with multiple lung metastasis found incidentally on chest X-ray.…”