Stromal Tumor Of Uncertain Malignant Potential Research Articles

Clinical and Pathological Features of Prostatic Stromal Tumor of Uncertain Malignant Potential: A Retrospective Study of 23 Chinese Cases

Introduction: Prostatic stromal tumor of uncertain malignant potential (STUMP) is a rare disease that may coexist with prostate stromal sarcoma (PSS). We aimed to analyze the histological and clinical features of STUMP. Methods: Twenty-three patients diagnosed with STUMP from 2008 to 2019 were included. Clinicopathological and follow-up information was collected. In the subgroup analysis, we divided the patients into a pure STUMP group (N = 18) and a mixed STUMP (STUMP coexisting with PSS) group (N = 5). Student’s t test was used to compare the 2 groups. Results: Patients had a mean age of 55.5 ± 19.4 years and an average follow-up time of 42.3 months. The mean prostate volume was 109.2 ± 73.5 cm³, and the mean prostate-specific antigen was 8.03 ± 10.5 ng/mL. In the subgroup analysis, 16.7% (2/12) of pure STUMP patients had disease progression, while 100% (3/3) of mixed STUMP patients suffered from recurrence. Compared with the pure STUMP group, the mixed STUMP group was younger (37.2 vs. 60.6 years, p = 0.013) and had lower expression of estrogen receptor and progesterone receptor (p = 0.004 and p < 0.001, respectively). Conclusion: STUMP is a rare disease with a relatively good prognosis. However, there is still a possibility of disease progression or coexistence with stromal sarcoma. Timely diagnosis and regular monitoring may be helpful in improving treatment outcomes.

Prostatic Stromal Tumors of Uncertain Malignant Potential

We present a 53-year-old man with a multilocular solid and cystic mass measuring 19 cm on cross-sectional imaging. After undergoing pelvic mass excision, final histopathology confirmed the diagnosis of primary prostatic stromal tumor of uncertain malignant potential (STUMP). Prostatic STUMPs are rare mesenchymal tumors with diverse histologic patterns. They are distinct from prostatic stromal sarcomas as they do not behave aggressively, although some may occasionally demonstrate local recurrence after resection. Due to their unpredictable malignant potential, lack of correlation between histologic patterns, and sarcomatous differentiation, these patients warrant surgical excision and close follow-up.

Whole-exome sequencing demonstrates recurrent somatic copy number alterations and sporadic mutations in specialized stromal tumors of the prostate

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). Fluorescence in situ hybridization was done on 9 cases and showed compatible chromosome 13 copy numbers with the WES results. STUMPs and the low-grade stromal sarcoma carried moderate tumor mutation burdens that ranged from 1.23 to 7.24 mutations per megabase, while the high-grade stromal sarcoma harbored a significantly higher mutation burden (11.55 mutations per megabase). Sporadic somatic mutations were observed, but no recurrent driver mutations could be discerned. In conjunction with prior array comparative genomic hybridization, we have demonstrated the consistent gene dosage profiles that support the clonal nature and the concept of specialized stromal tumors of the prostate as a distinctive tumor entity.

Round cell pattern of prostatic stromal tumor of uncertain malignant potential: a subtle newly recognized variant

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. We searched our database from 1999 to 2015 and identified 7 patients with round cell pattern out of a total number of 98 patients with STUMP. All 7 cases showed mildly increased stromal cellularity with rounded nuclei, diagnosed on core biopsies in 5 cases, transurethral resection in 1 case, and radical prostatectomy in 1 case. Some degree of glandular displacement was observed in 4 cases. In 2 of the cases, STUMP was not recognized histologically by the referring pathologists and was initially diagnosed as benign prostatic hyperplasia. As has been described with other patterns of STUMP, several cases showed associated epithelial proliferations that in some instances masked the neoplastic stromal process. The round cell pattern of STUMP is a new deceptively subtle pattern that may not be recognized as a neoplasm and may be misdiagnosed as benign prostatic hyperplasia. Although there was no direct evidence in our study that the round cell pattern of STUMP has the same behavior as other variants of STUMPs, increased recognition of this entity will hopefully lead to additional studies to further understand its malignant potential.

Prostatic Stromal Tumor of Uncertain Malignant Potential Which Was Difficult to Diagnose.

Here, we report a case of stromal tumor of uncertain malignant potential (STUMP) that was difficult to diagnose. A 53-year-old male was found to have a hard nodule on digital rectal examination; magnetic resonance imaging revealed a large nodule on the left side of the prostate, indicating prostate cancer. However, pathological diagnosis of the biopsy specimen was benign prostatic hyperplasia. Although a papillary tumor in the prostatic urethra was also seen on urethrocystoscopy, the tumor specimen obtained from transurethral resection was not malignant. The tumor in the prostatic urethra recurred only 3 months after transurethral resection, and pathological findings revealed benign hyperplasia not only in the stromal tissue but also in the epithelium; therefore, the prostate tumor was suspected to be STUMP. It took many prostate pathologists a long time to reach the final diagnosis of STUMP. STUMP is a rare benign tumor, difficult to diagnose, and sometimes transforms into stromal sarcoma. Thus, we should consider radical resection in such cases.

Stromal tumor of uncertain malignant potential of the prostate.

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. Owing to the rarity of this tumor, there is not yet a consensus on appropriate management. However, owing to the possibility of aggressive behavior, close management and consideration of definitive resection is warranted.

Incidental Prostatic Stromal Tumor of Uncertain Malignant Potential (STUMP): Histopathological and Immunohistochemical Findings

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. Furthermore, they often recur and this is why they are considered as neoplastic entities. STUMPs usually tend to be not aggressive, but occasional cases have been reported with an extension into adjacent tissues. A few cases develop a sarcomatous dedifferentiation. A 67-year-old male referred to the Department of Urology, Sapienza Rome University, with acute urinary retention (AUR) and bladder overdistention. Digital rectal examination (DRE) showed the presence of a severe prostatic hyperplasia and a transvesical prostatic adenomectomy (TVPA) was performed. The pathological evaluation performed at the Department of Pathology, Sapienza Rome University, revealed an incidental diagnosis of prostatic STUMP. The patient's follow-up is made every year with transrectal ultrasonography and nuclear magnetic resonance with spectroscopy, and every two years with a transperineal prostate biopsy to exclude a progression to a stromal sarcoma. After 5 years of follow-up the STUMP is still detectable but there is no sign of sarcoma. As a result of its relative rarity and lack of long-term follow-up, the prognosis of STUMP is unclear. Therapy varies from a wait-and-see approach to a radical retropubic prostatectomy.

Prostatic stromal tumor of uncertain malignant potential (STUMP) with unrecognized growth pattern

Prostatic stromal tumor of uncertain malignant potential (STUMP) with unrecognized growth pattern

A Case of Laparoscopic Radical Prostatectomy for a Prostatic Stromal Tumor of Uncertain Malignant Potential

Prostatic stromal tumor of uncertain malignant potential (STUMP) is a rare neoplasm with distinctive clinical and pathological characteristics. Here we report a case of laparoscopic radical prostatectomy performed in a patient with prostatic STUMP.

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

We report the case of a 68-year-old man with a stromal tumor of uncertain malignant potential (STUMP), which had metastasized to the lung. The patient complained of an enlarged mass in the anterior chest. Chest computed tomography (CT) showed a sternal abscess with multiple nodules in both lungs. A thoracoscopic lung biopsy of the nodules and incision/drainage of the sternal mass were performed simultaneously. CT of the pelvis revealed an enlarged prostate with irregular cystic lesions in the pelvis. Prostate biopsy was done and demonstrated hypercellular stroma with minimal cytological atypia, a distinct pattern of STUMP. The sternal abscess proved to be tuberculosis and the lung lesion was consistent with STUMP, which had spread from the prostate. However, to our knowledge, the tuberculous abscess might not be assoicated with STUMP in the lung. The patient refused surgical prostatectomy and was discharged with anti-tuberculosis medication. On one-year follow up, the patient had no evidence of disease progression.

Phyllodes Tumor of the Prostate

Prostatic soft tissue tumors other than nodular hyperplasia are very rare. Phyllodes tumor uncommonly arises in the prostate, and shares similarities to its counterpart in other organs such as the breast, including distinctive histopathologic appearance and protracted clinical course that often culminates in stromal overgrowth and metastases. The most important differential diagnostic considerations are stromal hyperplasia with atypical cells (benign variant of nodular hyperplasia) and stromal sarcoma (malignant). This review presents the complete clinical history of a patient with phyllodes tumor, including multiple recurrences over many years. Emphasis is placed on the criteria and clinical importance of exact histopathologic diagnoses rather than imprecise terms such as prostatic stromal tumor of uncertain malignant potential (STUMP) that erroneously lump benign and malignant processes together.

Assessing the Prognosis of Gastrointestinal Stromal Tumors

In recent years, immunohistochemical analysis for KIT (CD117) has made the once troublesome diagnosis of gastrointestinal stromal tumor (GIST) almost routine in most cases. This is particularly important now that an effective therapy—treatment with the kinase inhibitor imatinib mesylate (Gleevec)—is available for patients with unresectable or widely metastatic disease.1,2 Oncologists still sometimes fret that a diagnosis of GIST has been overlooked, but the recent attention given to KIT staining probably has resulted more in overdiagnosis than in missed opportunities to treat.3 Although there are GISTs with unusual morphologic (epithelioid, pleomorphic) and immunophenotypic (KIT weak or negative) characteristics, these represent only a minority of cases.4 The greater problem with GISTs today is in determining their prognosis rather than making their diagnosis. Great debates of past decades about the distinction between “benign” and “malignant” GISTs largely have been resolved in favor of the view that all GISTs have malignant potential; it is just a question of degree. Thus, the phrase “stromal tumor of uncertain malignant potential (STUMP)” still applies to the typical primary GIST, although it must be emphasized that it is the pathologist who is stumped, not the tumor. To stress the malignant potential of GISTs, many experts in the field routinely sign them out as gastrointestinal stromal sarcoma—a prudent diagnosis that nevertheless offers relatively little guidance to clinicians and their patients. How best, then, to assess the prognosis of a patient with a newly diagnosed primary GIST? There are a number of parameters that have been defined reproducibly as prognostically important in GISTs, including size, mitotic index, mucosal ulceration, necrosis, site of origin, and aneuploidy. Among these, size and mitotic index are the features emphasized in most published schemes, including the consensus guidelines published after a National Institutes of Health–National Cancer Institute–sponsored workshop held in April 2001.5 These guidelines recently were used in a large (600 cases), retrospective epidemiologic study by Kindblom and colleagues,6 in which it was found that the long-term survival of patients with low-risk and very-low-risk tumors was almost the same as that of the general population. Not surprisingly, high-risk and overtly malignant tumors, which constituted 20% to 30% of the total, had a much poorer prognosis. Yet even among these groups, there were long-term survivors (>15 years). For patients with intermediate-risk lesions, the survival was closer to that of the low-risk group than the highrisk group. This important study, the first in the post-KIT era, confirms 2 general observations about GISTs: (1) The great majority of very-low-risk, low-risk, and intermediate-risk GISTs behave in a benign manner. (2) Among these tumors, there is an unpredictable subset that behaves aggressively. Similar studies are ongoing and perhaps will result in fine-tuning of the consensus guidelines. It is doubtful, however, that any scheme based solely on tumor size and mitotic index will permit the clinician, when meeting a patient with a typical primary GIST, to interpret the pathology report with anything more than vaguely legalistic phrases (“Mr Smith, it is more likely than not that....”). Such uncertainty was tolerable when there were no effective therapies for recurrent or metastatic GISTs (chemotherapy and radiation treatment do not work in this disease). With the introduction of imatinib, however, risk assessment of GISTs has taken on new importance. The prognosis of patients with advanced GISTs has changed dramatically with imatinib therapy.1,2 Based on an