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Mod Pathol 2018 Jan;31(S1):S133-142

Robert J Tomsich Pathology and Laboratory Medicine Institute, Anatomic Pathology, Cleveland Clinic, Cleveland, OH, USA.

Mesenchymal tumors of the prostate are rare but often cause considerable diagnostic difficulty when encountered. These may be either benign or malignant and can arise within the prostate gland or in adjacent tissues. This review covers prostatic stromal proliferations (prostatic stromal tumor of uncertain malignant potential and stromal sarcoma), solitary fibrous tumor, myofibroblastic proliferations, smooth muscle neoplasms (leiomyoma and leiomyosarcoma), gastrointestinal stromal tumor, schwannoma, rhabdomyosarcoma, sarcomatoid carcinoma, postradiation sarcoma, and mixed epithelial stromal tumor of the seminal vesicle. Read More

Hum Pathol 2018 06 16;76:9-16. Epub 2017 Dec 16.

Department of Pathology, The Johns Hopkins University School of Medicine, 21205 Baltimore, MD; Department of Pathology, The James Buchanan Brady Urological Institute, 21205 Baltimore, MD; Department of Pathology, The Johns Hopkins Hospital, 21287 Baltimore, MD. Electronic address:

In a previous array comparative genomic hybridization study, we detected common deletions of chromosomes 13 and 14 in prostatic stromal sarcoma and stromal tumor of uncertain malignant potential (STUMP). In this study, we performed whole-exome sequencing (WES) and fluorescence in situ hybridization to explore somatic mutations in 1 low-grade stromal sarcoma, 1 high-grade stromal sarcoma, and 12 STUMPs including 5 cases of degenerative atypia type, 1 myxoid type, 1 phyllodes type, and 5 cases of recently described round cell type. WES was successful on 13 cases that revealed frequent somatic copy number alterations including losses of chromosomes 13 (11 cases), 14 (11 cases), and 1p (9 cases), and partial or complete loss of chromosome 10 (7 cases). Read More

Diagn Pathol 2017 Jul 7;12(1):50. Epub 2017 Jul 7.

Pathology Unit, Istituto Nazionale Tumori I. R. C. C. S. "Fondazione Pascale", Naples, Italy.

Background: Solitary fibrous tumor is an uncommon soft tissue neoplasm with intermediate biological behavior, which rarely metastasizes. Malignant solitary fibrous tumor, although not clearly defined, is rarely described in the prostate. The present case is characterized by some peculiarities if compared with previously reported cases of prostatic malignant solitary fibrous tumor. Read More

Arch Iran Med 2016 Jul;19(7):488-90

Pathology Department, Shiraz University of Medical Sciences, Shiraz, Iran.

Background: Prostatic stromal tumors of uncertain malignant potential (STUMPs) are rare tumors arising from the specialized prostatic stroma. These tumors share certain histological and clinical features of benign prostatic hyperplasia, resulting in misdiagnosis of STUMP as prostatic hyperplasia. However, in contrast to prostatic hyperplasia, occasional cases have been documented to recur rapidly after resection and few of them have progressed to prostatic stromal sarcoma and distant metastasis. Read More

Radiographics 2016 Jul-Aug;36(4):1055-75. Epub 2016 Jun 17.

From the Department of Radiology and Biomedical Imaging (Y.L., J.M., S.C.B., A.C.W.) and Department of Pathology (J.S.), University of California, San Francisco, 505 Parnassus Ave, M-391, San Francisco, CA 94143-0628; Department of Radiology, Sir Ganga Ram Hospital, New Delhi, India (S.S.); and Department of Diagnostic Radiology, Oregon Health and Science University, Portland, Ore (F.V.C.).

Recent advances in magnetic resonance (MR) imaging of the prostate gland have dramatically improved the ability to detect and stage adenocarcinoma of the prostate, one of the most frequently diagnosed cancers in men and one of the most frequently diagnosed pathologic conditions of the prostate gland. A wide variety of nonadenocarcinoma diseases can also be seen with MR imaging, ranging from benign to malignant diseases, as well as infectious and inflammatory manifestations. Many of these diseases have distinctive imaging features that allow differentiation from prostate acinar adenocarcinoma. Read More

Hum Pathol 2016 06 1;52:68-73. Epub 2016 Feb 1.

Department of Pathology, The Johns Hopkins Medical Institutions, Baltimore, MD 21231; Department of Urology, The Johns Hopkins Medical Institutions, Baltimore, MD 21231; Department of Oncology, The Johns Hopkins Medical Institutions, Baltimore, MD 21231. Electronic address:

Prostatic stromal tumor of uncertain malignant potential (STUMP) is a distinct entity which includes several different patterns. Four patterns of STUMP have been described including stroma with (1) degenerative atypia, (2) hypercellular spindle cells, (3) myxoid spindle cells, and (4) phyllodes-like pattern. The current study identified a novel round cell pattern. Read More

Urol Case Rep 2015 Sep 15;3(5):175-7. Epub 2015 Jul 15.

Brady Urological Institute, Johns Hopkins Medical Institutions, Baltimore, MD 21287, USA.

Stromal tumors of uncertain malignant potential (STUMP) are rare diagnoses in the evaluation of elevated PSA. The management of STUMP in the setting of an elevated PSA is challenging, as STUMP may have a benign clinical course. In this report, we describe a patient who was found to have a PSA >500 ng/ml and a large STUMP. Read More

Int J Surg Case Rep 2015 4;17:82-4. Epub 2015 Nov 4.

Department of General Surgery, The Canberra Hospital Building 6, Level 1, Yamba Drive, Garran, ACT 2605, Australia. Electronic address:

Introduction: Prostatic stromal sarcomas account for about 0.1% of all prostatic malignancies. Local recurrence into bladder, seminal vesicles and rectum has been documented. Read More

Hinyokika Kiyo 2015 Jun;61(6):245-8

The Department of Pathology, Ikeda City Hospital.

A 77-year-old man was seen at our hospital with the chief complaint of pollakisuria. Magnetic resonance imaging (MRI) showed a 25 mm cystic tumor with solid components behind the prostate. A transrectal biopsy for the prostate showed no evidence of malignancy. Read More

Adv Anat Pathol 2015 Mar;22(2):113-20

*Department of Medicine, University of Calgary †Department of Pathology and Laboratory Medicine, University of Calgary and Calgary Laboratory Services, Calgary, AB, Canada.

In contrast to the common tumors of the prostate, seminal vesicle demonstrates low potential for neoplastic proliferation. Of the rare primary seminal vesicle tumors, adenocarcinoma is the most common, but there are also rare seminal vesicle neoplasms which demonstrate epithelial and stromal components. These neoplasms have been described in the literature under various names, including "epithelial-stromal tumor," "cystic epithelial-stromal tumor," "cystadenoma," "cystomyoma," "mesenchymoma," "Müllerian adenosarcoma-like tumor," "phyllodes tumor," and "cystosarcoma phyllodes. Read More

Arch Pathol Lab Med 2014 Nov;138(11):1542-5

From the Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha.

Stromal tumor of uncertain malignant potential (STUMP) of the prostate is a rare tumor with a variable and unpredictable clinical course. Many STUMPs are diagnosed incidentally and never progress, while others may invade locally and rapidly recur after surgical intervention, and yet others may lead to distant metastasis and death. A wide array of histologic patterns is encompassed by STUMP, and distinguishing these tumors from prostatic stromal sarcoma or other causes of stromal expansion often proves difficult. Read More

Ann Pathol 2014 Jun 22;34(3):233-6. Epub 2014 May 22.

Service d'urologie, CHU de Nantes, CHU Hôtel-Dieu, 1, place Alexis-Ricordeau, 44000 Nantes, France. Electronic address:

We report the case of a patient affected by a voluminous prostatic tumor for which the histological analysis conclude in a stromal tumor of uncertain malignant potential. This type of tumor is rare, but requires to be individualized to differentiate it from a benign prostatic hyperplasia or a sarcoma of the prostate. The therapeutic care must be made keeping in mind the risk of degeneration towards a malignant shape. Read More

Asian J Androl 2014 Sep-Oct;16(5):794-5

Minimally Invasive Urology Center, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, China.

Urol Case Rep 2014 Mar 12;2(2):43-4. Epub 2014 Mar 12.

Division of Urology, The Hospital of the University of Pennsylvania, Philadelphia, PA.

Prostate stromal tumor of uncertain malignant potential is a term used to describe a specialized proliferation of stromal cells within the prostate. Most of these tumors tend to be benign, but some can present with local invasion or progress to prostatic stromal sarcoma with distant metastasis. We report a case of a 62-year-old male patient who presented to us with a diagnosis of stromal tumor of uncertain malignant potential. Read More

Mod Pathol 2013 Nov 14;26(11):1536-43. Epub 2013 Jun 14.

Department of Pathology, Taipei Veterans General Hospital, National Yang-Ming University, Taipei, Taiwan.

Specialized stromal tumors of the prostate encompass stromal sarcoma and stromal tumors of uncertain malignant potential (STUMP). The molecular signature associated with stromal sarcoma and STUMP has not been unraveled. The study was conducted to detect the chromosomal imbalances in stromal sarcoma and STUMP by using array comparative genomic hybridization (aCGH). Read More

Hinyokika Kiyo 2013 Feb;59(2):137-40

The Department of Urology, Sapporo Medical University School of Medicine, Japan.

A 56-year-old man visited a local hospital after experiencing urinary frequency for five years. A digital rectal examination revealed a markedly enlarged prostate and his serum prostate specific antigen (PSA) was 9.0 ng/ml. Read More

Pathology 2013 02;45(2):104-15

Department of Pathology, Messejana State Hospital, Fortaleza, CE, Brazil.

Mesenchymal tumours of the urinary bladder and prostate are infrequent neoplasms. The body of literature is growing with isolated case reports and short series, and the majority of cases are benign neoplasms. Other than stromal tumour of uncertain malignant potential and prostatic stromal sarcoma, both neoplasms derived from the specific prostatic stroma, the mesenchymal neoplasms in these locations are identical to their counterparts seen in other organs. Read More

Prog Urol 2012 Oct 12;22(12):688-91. Epub 2012 Jul 12.

Service d'urologie, CHU Hôtel-Dieu, Nantes, France.

Prostatic Stromal Tumors of Uncertain Malignant Potential (STUMP) are rare tumor of the prostate of mesenchymal origin, accounting, with sarcoma for 0.1-0.2% of all malignant prostatic tumours. Read More

Hinyokika Kiyo 2012 May;58(5):255-8

The Department of Urology, Gifu Prefectural General Medical Center.

Prostatic stromal tumor of uncertain malignant potential (STUMP) is a rare neoplasm characterized by an atypical, unique stromal proliferation of the prostate. Two patients consulted our hospital with the complaint of urinary retardation. We performed holmium laser enucleation of the prostate since by digital rectal examination, magnetic resonance imaging and needle biopsy suggested benign prostatic hyperplasia. Read More

Urologia 2012 ;79(1):65-8

Department of Urology, Sapienza Rome University, Rome, Italy.

Stromal prostate tumors are rare neoplastic proliferative lesions that have been classified into prostatic stromal tumor of uncertain malignant potential (STUMP) and prostatic stromal sarcoma (SS) based on these criteria: stromal cellularity, presence of mitotic figures, necrosis, and stromal overgrowth. A prostatic stromal tumor of uncertain malignant potential (STUMP) is a non-epithelial, mesenchymal spindle-cell tumor that can be classified as a specialized stromal tumor of the prostate. STUMPs have the capability to diffusely infiltrate the prostate gland and extend into adjacent tissues. Read More

Pathol Int 2012 Jan;62(1):69-71

Br J Radiol 2011 Oct;84(1006):e194-6

Ribeirao Preto School of Medicine, University of Sao Paulo, Ribeirao Preto, Sao Paulo, Brazil.

Prostatic stromal tumours are rare neoplasias that include benign, malignant and borderline lesions. Stromal tumour of uncertain malignant potential (STUMP) has been recently described and only a few reports exist in the literature. As a rare and distinct neoplasia, to date, there is no description of MRI findings of prostate STUMP. Read More

Am J Surg Pathol 2011 Jun;35(6):898-903

Department of Pathology, The Johns Hopkins Hospital, 401 North Broadway Street, Baltimore, MD 21231, USA.

Stromal tumors of uncertain malignant potential (STUMPs) are rare tumors characterized by an atypical, unique stromal proliferation of the prostate. Various stromal proliferations of STUMPs have been described; however, epithelial proliferations occurring within the STUMP have not been systematically described to date. We reviewed 89 cases of STUMP from our consultation service from 1990 to 2010. Read More

Case Rep Pathol 2011 13;2011:252805. Epub 2011 Dec 13.

Departments of Pathology, General Hospital C.G. Mazzoni, 63100 Ascoli Piceno, Italy.

Primary sarcoma tumours of the prostate are rare and are classified, according to their histology, as stromal tumours of uncertain malignant potential (STUMP) and stromal prostatic sarcoma (PS; low and high grade). We describe a case of a 71-year-old man that developed progressive urinary obstruction symptoms and was subjected to a transurethral prostatic resection (TURP). Histologically, there is a diffuse proliferation of epithelioid and spindle cells that showed rare atypical mitotic figures. Read More

Hinyokika Kiyo 2010 Apr;56(4):237-40

Department of Urology, Osaka University Graduate School of Medicine.

A 64-year-old male was referred to our hospital with a prostate tumor accompanying a huge prostatic cyst. He had been followed up for 10 years by another urologist, and received several prostate biopsies, which failed to make a definite diagnosis. We carefully reviewed the biopsy slides and diagnosed the lesion as prostatic stromal tumor of uncertain malignant potential (STUMP). Read More

Aktuelle Urol 2010 May 4;41(3):197-9. Epub 2010 Mar 4.

Klinik und Poliklinik für Urologie, Universitätsklinikum Schleswig-Holstein (UKSH), Campus Lübeck.

A prostatic stromal tumour of uncertain malignant potential (STUMP) is a non-epithelial, mesenchymal spindle-cell tumour that can be classified as a specialised stromal tumour of the prostate. Although in most cases STUMP is not of an aggressive nature, occasional cases have been documented with an extension into adjacent tissues or recurrence after resection. A minority of cases develop a sarcomatous dedifferentiation. Read More

J Oncol 2009 22;2009:241270. Epub 2009 Dec 22.

Department of Urology, Ev.-Luth. Diakonissen Hospital Flensburg, 24939 Flensburg, Germany.

Cystic epithelial-stromal tumors of the prostate are rare, with 82 cases reported in literature. These cases have been published under a variety of diagnoses, including phyllodes tumor and prostatic stromal proliferation of uncertain malignant potential as well as a malignant tumor called "prostatic stromal sarcoma". We report a case of a 60-year-old man with the histological diagnosis of phyllodes tumor of the prostate in transurethral resection specimen. Read More

Hinyokika Kiyo 2009 Aug;55(8):503-7

Department Urology, Jichi Medical University.

A 63-year-old man with a retroperitoneal tumor found incidentally was referred to our hospital. Computed tomography showed a tumor ventrally adjacent to urinary bladder and prostate. Pathological examination of retroperitoneal tumor specimens obtained by percutaneous needle biopsy revealed hypercellularity of spindle cells positive for CD 34. Read More

Hinyokika Kiyo 2008 May;54(5):377-81

Department of Urology, Osaka University Graduate School of Medicine.

Sarcomas and related proliferative lesions of specialized stroma of prostate are rare. Lesions have been classified into prostatic stromal tumor of uncertain malignant potential (STUMP) and prostatic stromal sarcoma (SS) based on the degree of stromal cellularity, presence of mitotic figures, necrosis, and stromal overgrowth. STUMPs are considered neoplastic, based on the observations that they may diffusely infiltrate the prostate gland and extend into adjacent tissues, and often recur. Read More

Urologe A 2008 Jun;47(6):753-6

Klinik für Urologie, Städtisches Klinikum Dresden-Friedrichstadt, Friedrichstrasse 41, Dresden, Germany.

Stromal tumor of the prostate of uncertain malignant potential (STUMP) is an extremely rare entity. The clinical symptoms are nonspecific for this tumor. An abnormal digital rectal examination or an elevated prostate-specific antigen level is possible but not obligatory. Read More

Indian J Pathol Microbiol 2007 Oct;50(4):826-8

Department of Pathology, Pt. B.D.S. PGIMS, Rohtak.

Proliferative lesions of specialized prostatic stroma are rare with only few isolated case reports documented in literature. These lesions are histologically characterized by exuberant proliferation of prostatic stroma with variable number of normal and hyperplastic glands. Recently this group of tumors have been labeled as prostatic stromal proliferations of uncertain malignant potential (PSPUMP). Read More

Urology 2008 Jun 20;71(6):1226.e13-5. Epub 2008 Feb 20.

Department of Urology, Johannes Gutenberg-University, Medical School, Mainz, Germany.

Several benign and malignant nonepithelial and stromal-like lesions arise in the prostate. Because such lesions are rare, their recognition is essential, because treatment and prognosis depend on an adequate pathohistologic classification. We report a case of an 83-year-old man with a stromal tumor of the prostate of uncertain malignant potential (STUMP). Read More

Nihon Hinyokika Gakkai Zasshi 2007 Sep;98(6):781-5

Hachinohe City Hospital, Department of Urology, Japan.

A 55 year-old man complained dysuria and visited to our hospital. Physical examination showed firm large mass occupying whole abdomen. Computed tomography (CT) demonstrated a huge retroperitoneal tumor which compressed intestine, liver, kidney, and urinary bladder. Read More

Mod Pathol 2007 Jan;20(1):148-58

Department of Pathology, The Johns Hopkins Hospital, Baltimore, MD 21231, USA.

Prostatic spindle cell lesions are diagnostically challenging and encompass a broad array of benign and malignant processes. A subset of these lesions arises only within the prostate and generally represents entities that originate from the prostate epithelium or stroma, such as sclerosing adenosis, sarcomatoid carcinoma, stromal tumors of uncertain malignant potential (STUMP), and stromal sarcoma. Another subset of spindle cell tumors that involve the prostate are also found at other sites and include solitary fibrous tumor, leiomyosarcoma, and neural lesions among others. Read More

Am J Surg Pathol 2006 Jun;30(6):694-704

Department of Pathology, The Johns Hopkins Medical Institutions, Baltimore, MD 21231, USA.

Specialized stromal tumors of the prostate encompass stromal sarcoma and stromal tumors of uncertain malignant potential (STUMP). As a result of their relative rarity and lack of long-term follow-up, the prognosis of STUMP is unclear. We studied 50 cases of STUMP and stromal sarcoma with regard to their clinical presentation and follow-up. Read More

Hinyokika Kiyo 2005 Dec;51(12):843-6; discussion 846-7

The Department of Urology, Osaka General Medical Center.

Sarcomas and related proliferative lesions of specialized prostatic stroma are rare. Lesions have been classified into prostatic stromal tumor of uncertain malignant potential (P-STUMP) and prostatic stromal sarcoma based on the degree of stromal cellularity, presence of mitotic figures, necrosis, and stromal overgrowth. STUMPs are considered neoplastic, based on the observations that they may diffusely infiltrate the prostate gland and extend into adjacent tissues, and often recur. Read More

Ann Acad Med Singapore 2005 Aug;34(7):441-2

Department of General Surgery, Changi General Hospital, Singapore.

Clinical Presentation: A 56-year-old Chinese male with previously diagnosed prostatic stromal tumour of uncertain malignant potential (STUMP) presented with urinary retention 6 years after transurethral resection of prostate (TURP).

Treatment And Outcome: Cystoscopy showed a papillary tumour of the prostatic urethra causing near-complete obstruction. Repeat TURP was performed. Read More

Am J Surg Pathol 2004 Dec;28(12):1609-14

Department of Pathology, Johns Hopkins Hospital, Baltimore, MD 21231, USA.

Inflammatory myofibroblastic tumor (IMT) of the bladder is an uncommon myofibroblastic spindle cell proliferation. Because of its cytologic features and infiltrative nature, it may be difficult to distinguish histologically from sarcomatous proliferations such as sarcomatoid urothelial carcinoma, leiomyosarcoma, and embryonal rhabdomyosarcoma. Recently, anaplastic lymphoma kinase (ALK) gene translocations or ALK protein expression in IMT has been reported, especially in patients of relatively young ages. Read More

Indian J Cancer 2004 Jul-Sep;41(3):129-32

Department of Pathology, Government Medical College, Nagpur, India.

Although glandular and stromal proliferations of prostate are very common in adult men, neoplastic proliferations of prostatic stroma are distinctly uncommon. These tumors are now grouped as Prostatic Stromal Proliferations of Uncertain Malignant Potential (PSPUMP). Phyllodes tumor of the prostate is a rare neoplasm in this group with cellular, sarcomatoid stroma and benign hyperplastic glands. Read More

J Urol 2004 Sep;172(3):894-9

Bostwick Laboratories, 2807 North Parham Road, Richmond, VA 23294, USA.

Purpose: Phyllodes tumor of the prostate is a rare neoplasm of uncertain malignant potential. We studied a large series of phyllodes tumors to define the combination of histological features that are most useful for predicting patient outcome.

Materials And Methods: A total of 23 cases were obtained from our collective files from 1973 to 2002, and numerous clinical and pathological features were evaluated. Read More

J Urol 2002 Oct;168(4 Pt 1):1493-4

Department of Urology, Mount Sinai School of Medicine, New York, New York, USA.

Adv Anat Pathol 1998 Nov;5(6):359-66

Department of Pathology, University of Iowa, Iowa City, USA.

This commentary addresses the newly proposed classification of the rare atypical prostatic stromal lesions of the prostate. The entity called "prostatic stromal proliferation of uncertain malignant potential" apparently has a benign behavior. The entity "prostatic stromal sarcoma" might have a malignant potential, but its line of differentiation is still unclear. Read More

Am J Surg Pathol 1998 Feb;22(2):148-62

Department of Pathology, Memorial Sloan-Kettering Cancer Center, New York, New York 10021, USA.

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. Read More