Prostate gland & seminal vesicles
Stromal tumors
Stromal sarcoma
Author: Kenneth A. Iczkowski, M.D.
Editorial Board Member: Debra L. Zynger, M.D.
Topic Completed: 1 June 2017
Minor changes: 30 October 2020
Copyright: 2003-2021, PathologyOutlines.com, Inc.
PubMed search: Prostatic stromal sarcoma
Related topics: Stromal proliferation of uncertain malignant potential
Table of Contents
Definition / general | Essential features | ICD coding | Epidemiology | Clinical features | Radiology description | Radiology images | Prognostic factors | Case reports | Treatment | Microscopic (histologic) description | Microscopic (histologic) images | Positive stains | Negative stains | Molecular / cytogenetics description | Differential diagnosis | Board review style question #1 | Board review style answer #1Cite this page: Iczkowski KA. Stromal sarcoma. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/prostatestromalsarcoma.html. Accessed March 7th, 2021.
Definition / general
- A rare entity (Pathology 2013 Feb;45:104)
- Usually presents with urinary retention; also abnormal digital rectal examination, hematuria or hematospermia, palpable rectal mass
- Includes phyllodes tumors (like those of the breast)
Essential features
- Cellular pleomorphism exceeding that of stromal proliferation of undetermined malignant potential
- Necrosis
- Mitotic activity
- Extension outside the prostate
ICD coding
- C61 Malignant neoplasm of prostate
Epidemiology
- Fewer than 30 reported cases
- Mean age 54 years, peak incidence in 50s and 60s but ranges from 14 to 86 (Am J Surg Pathol 1998;22:148)
Clinical features
- The most common presentation is bladder outlet obstruction, followed by abnormal digital rectal exam, hematuria and rectal fullness (Am J Surg Pathol 2006;30:694)
- Serum PSA is usually normal
Radiology description
- MRI shows a multinodular mass with homogeneous or heterogeneous low signal intensity on T1 weighted imaging and heterogenous high signal intensity on T2 weighted imaging (Oncol Lett 2016;11:2542)
Radiology images
Images hosted on other servers:
T1-weighted axial MRI image
T2-weighted axial MRI image
Prognostic factors
- Low grade stromal sarcoma can locally invade, whereas high grade stromal sarcoma has the potential to metastasize
- Metastatic sites include
- Lymph nodes (J Surg Case Rep 2016 May 3;2016, Oncol Lett 2016;11:2542)
- Liver (Mod Pathol 2013;26:1536)
- Subcutaneous (Int J Surg Case Rep 2015;17:82)
Case reports
- 14 year old boy with fatal case (Rare Tumors 2014;6:5607)
- 31 year old with stromal sarcoma with rhabdoid features (Ann Diagn Pathol 2010;14:453)
- 32 year old Chinese man (Oncol Lett 2016;11:2542)
- 42 year old man with subcutaneous metastasis of tumor 5 years after prostatectomy (Int J Surg Case Rep 2015;17:82)
- 52 year old with recurrent tumor (J Clin Pathol 2007;60:330)
- 66 year old with 8 cm mass extending to bladder (J Surg Case Rep 2016 May 3;2016)
- 71 year old with urinary obstruction (Case Reports in Pathology 2011;2011 (Article ID 252805))
Treatment
- Can be managed by robotic procedure but surgery alone is inadequate (Korean J Urol 2014;55:620, J Surg Case Rep 2016 May 3;2016)
- Tumor does respond to chemotherapy and radiotherapy (Rare Tumors 2014;6:5607)
Microscopic (histologic) description
- Greater cellularity, mitotic activity, necrosis and stromal overgrowth than stromal tumor of uncertain malignant potential
- Storiform and infiltrative growth pattern
- Sarcomas are subdivided into low grade and high grade based on mitotic rate, necrosis and degree of atypia (Am J Surg Pathol 2006;30:694)
- There may be either stromal elements with benign glands resembling malignant breast phyllodes tumors or pure stromal elements
Microscopic (histologic) images
Images hosted on other servers:
Various images
Histological features
Positive stains
- Vimentin (100%), CD34 (100%), progesterone receptor (85%), desmin (50%), smooth muscle actin (33%), HHF35 (25%)
Molecular / cytogenetics description
- Both prostatic stromal sarcoma (all 4 cases) and smooth muscle tumors of uncertain malignant potential (STUMP) (7 of 8 cases) share chromosomal aberrations by array comparative genomic hybridization (aCGH); most common was loss of chromosome 13 followed by losses of chromosomes 14 or 10; thus, sarcoma and STUMP are in the same family of tumors and aCGH is not discriminatory (Mod Pathol 2013;26:1536)
Differential diagnosis
- Stromal proliferation of uncertain malignant potential: more common than stromal sarcoma, no marked atypia or necrosis
- Leiomyoma: much more common; consistently positive for smooth muscle markers
- Gastrointestinal stromal tumor: rule out using CD117
Board review style question #1
Two of the most consistently positive and useful markers for prostatic stromal
sarcoma are:
A. Estrogen receptor and CD34
B. S100 protein and HHF35 muscle marker
C. CD34 and progesterone receptor
D. Desmin and S100 protein
E. Smooth muscle actin and estrogen receptor
A. Estrogen receptor and CD34
B. S100 protein and HHF35 muscle marker
C. CD34 and progesterone receptor
D. Desmin and S100 protein
E. Smooth muscle actin and estrogen receptor
Board review style answer #1
