In 2013, the World Health Organization defined perivascular epithelioid cell tumor (PEComa) as \"a mesenchymal tumor which shows a local association with vessel walls and usually expresses melanocyte and smooth muscle markers.\" This generic definition seems to better fit the PEComa family, which includes angiomyolipoma, clear cell sugar tumor of the lung, lymphangioleiomyomatosis, and a group of histologically and immunophenotypically similar tumors that include primary extrapulmonary sugar tumor and clear cell myomelanocytic tumor. Clear cell tumors with this immunophenotypic pattern have also had their malignant variants described. When localizing to the liver, preoperative radiological diagnosis has proven to be very difficult, and most patients have been diagnosed with hepatocellular carcinoma, focal nodular hyperplasia, hemangioma, or hepatic adenoma based on imaging findings. Examples of a malignant variant of the liver have been described. Finally, reports of malignant variants of these lesions have increased in recent years. Therefore, we support the use of the Folpe criteria, which in 2005 established the criteria for categorizing a PEComa as benign, malignant, or of uncertain malignant potential. Although they are not considered ideal, they currently seem to be the best approach and could be used for the categorization of liver tumors.

A 12-year-old adolescent was diagnosed with a right-sided solid mass in the round ligament of the uterus. The chief complaints were abdominal pain and pelvic discomfort. She underwent laparoscopic tumor resection. Histological examination demonstrated a trabecular growth pattern of epithelioid cells with mitotic activity (3 per 50 HPF), which expressed melanocytic and myoid markers. Due to aforementioned findings, a final diagnosis of perivascular epithelioid cell tumor (PEComa) with uncertain malignant potential was made. To the best of our knowledge, this localization of PEComa is considered to be infrequent with only occasionally reported cases.

Smooth muscle tumors that cannot be histologically classified as leiomyomas or leiomyosarcomas are defined as smooth muscle tumors of uncertain malignant potential. The location of these tumors in the nose is very rare, and the appropriate surgical extent to manage these neoplasms has not been adequately defined. Here we describe the case of a 16-year-old female adolescent who consulted due to a vascular-like tumor in the right nasal cavity who was successfully treated with intranasal surgery. The histological diagnosis was smooth muscle tumor of uncertain malignant potential. Given that these neoplasms are rare, the uncommon location in the nose, and the lack of evidence indicating the extent of surgery, it is relevant to describe and discuss this clinical case.
Los tumores de músculo liso que no pueden ser clasificados según su histología como leiomiomas o leiomiosarcomas se denominan tumores de músculo liso de comportamiento maligno incierto. La localización nasal de estos tumores es muy infrecuente y la extensión adecuada de la cirugía para tratar estas neoplasias no está bien definida. Se describe el caso clínico de una adolescente de 16 años, que consultó por padecer un tumor de aspecto vascular en la cavidad nasal derecha y que fue tratada con éxito mediante cirugía intranasal. El diagnóstico histológico fue tumor de músculo liso de comportamiento maligno incierto. Por la rareza de estas neoplasias, su infrecuente localización nasal y la falta de evidencia que soporte cuál debe ser la extensión de la cirugía, es relevante la descripción y discusión del caso clínico.

OBJECTIVE: to analyse the clinical-pathological characteristics, treatment, and evolution of uterine smooth muscle tumours with uncertain malignant potential (STUMP) diagnosed in the Salamanca University Hospital with the implementation of the 2014 WHO criteria.
METHODS: a retrospective descriptive study of patients diagnosed with STUMP from January 2015 to March 2023 at the Salamanca University Hospital. Demographic data, preoperative clinical data, treatment, complications, therapeutic results, anatomopathological findings and recurrence time were obtained.
RESULTS: a total of four patients were identified and included in the study. The mean age at diagnosis was 48 years (range 36-67). The surgical indications were abnormal uterine bleeding, compressive symptoms, and the growth of a pelvic mass suspected to be a degenerated myoma from the residual cervix after a subtotal hysterectomy 6 years earlier. In all cases, a laparotomic procedure was performed. A total hysterectomy, sub-total hysterectomy, and the excision of the cervix with STUMP localization were accomplished in two, one, and one patient, respectively. The mean diameter of the tumour pieces was 13 cm (range 8-17 cm), with a mean volume of 816 cc (range 234-1467 cc). The mean follow-up was 47 months, with no recurrence to date.
CONCLUSIONS: STUMPs are a heterogeneous group of tumours with a difficult-to-predict clinical evolution. In most cases, their diagnosis is histological after performing surgery for suspected leiomyoma. Due to their low incidence, there are no specific guidelines for their treatment and control. However, considering their potential risk of recurrence and metastasis, it is advisable to maintain six-monthly controls for 5 years and then annual controls for 5 years more.

The heterogeneous group of B3 lesions in the breast harbors lesions with different malignant potential and progression risk. As several studies about B3 lesions have been published since the last Consensus in 2018, the 3rd International Consensus Conference discussed the six most relevant B3 lesions (atypical ductal hyperplasia (ADH), flat epithelial atypia (FEA), classical lobular neoplasia (LN), radial scar (RS), papillary lesions (PL) without atypia, and phyllodes tumors (PT)) and made recommendations for diagnostic and therapeutic approaches. Following a presentation of current data of each B3 lesion, the international and interdisciplinary panel of 33 specialists and key opinion leaders voted on the recommendations for further management after core-needle biopsy (CNB) and vacuum-assisted biopsy (VAB). In case of B3 lesion diagnosis on CNB, OE was recommended in ADH and PT, whereas in the other B3 lesions, vacuum-assisted excision was considered an equivalent alternative to OE. In ADH, most panelists (76%) recommended an open excision (OE) after diagnosis on VAB, whereas observation after a complete VAB-removal on imaging was accepted by 34%. In LN, the majority of the panel (90%) preferred observation following complete VAB-removal. Results were similar in RS (82%), PL (100%), and FEA (100%). In benign PT, a slim majority (55%) also recommended an observation after a complete VAB-removal. VAB with subsequent active surveillance can replace an open surgical intervention for most B3 lesions (RS, FEA, PL, PT, and LN). Compared to previous recommendations, there is an increasing trend to a de-escalating strategy in classical LN. Due to the higher risk of upgrade into malignancy, OE remains the preferred approach after the diagnosis of ADH.

Stromal tumour of uncertain malignant potential (STUMP) is exceedingly rare. Diagnosis and management of STUMP present a challenge to the urologist due to the absence of specific clinical findings and its unpredictable clinical course. Thus, radical resection is often recommended. Here, we present a case of a 64-year-old male, who presented with mild obstructive voiding symptoms with a raised age-specific prostate-specific antigen (PSA) of 3.1. Magnetic resonance imaging (MRI) showed an area of suspicion, in an area thought to be the left seminal vesicle, containing a malignant lesion within it. Biopsy of this area and the prostate confirmed concurrent prostatic STUMP and Gleason 3+3=6 adenocarcinoma of the prostate, managed with robotic-assisted laparoscopic radical prostatectomy with wide local excision.

Background: This study aimed to systematically review the existing literature on uterine smooth muscle tumor of uncertain malignant potential (STUMP) to provide information about characteristics and outcomes of patients and the risk factors for recurrence over a period of 60 years (1960−2021). Methods: According to PRISMA guidelines, we searched for \"uterine smooth muscle tumor of uncertain malignant potential\" in PubMed (all fields) and Scopus (Title/Abstract/Keywords) databases (accessed on 1 January 2022). Relevant articles were obtained in full-text format and screened for additional references. The only filter used was the English language. Studies including full case description of patients with histopathological diagnosis of STUMP in accordance with Stanford criteria were included. Results: Thirty-four studies, including 189 cases, were included. The median age was 43 years, and in 21.5% of cases there was a recurrence of the disease. Bivariate analysis showed a significant association between use of morcellation without bag and risk of recurrence (p = 0.001). Unprotected morcellation during demolitive or conservative surgery was independently associated with a higher risk of disease recurrence with a relative risk of 2.94 (p < 0.001). A significant progressive decrease in the recurrence rate was observed over time (r = −0.671, p = 0.008). The percentage of patients who underwent surgery followed by in-bag protected morcellation significantly increased after the publication of the U.S. Food and Drug Administration alert about the risk linked to this procedure (p = 0.01). Conclusions: Unprotected morcellation of the lesion is associated with the relapse of the disease. However, this clinical condition showed a drastic decrease over time. This could likely be due to the increased awareness by surgeons of the importance of customizing surgical treatment.

Histopathological diagnosis of papillary thyroid carcinomas (PTCs) is prone to significant observer variation due to different thresholds of RAS-like nuclear changes among pathologists. This gap recently widened due to a defensive attitude by Western pathologists where malpractice litigation is significant. Cases with delicate RAS-like nuclear changes are follicular adenomas when they are noninvasive, follicular carcinomas when invasive, and follicular variant PTCs when they have fully developed PTC-type nuclear features in Asian practice. The different diagnostic threshold of PTC nuclear features resulted in a high (50-90%) incidence of BRAFV600E mutation of PTCs in most Asian countries, whereas it was low (35-50%) in most Western patient cohorts. The contamination of indolent RAS-like tumors in the malignant PTC category in Western patient cohorts explains why the BRAFV600E gene test identifies aggressive PTCs. However, the BRAFV600E test has no prognostic value for Asian PTC patients because most biologically benign or low-risk RAS-like tumors are excluded from PTC. All prognostic analyses of thyroid carcinomas before 2017 must be re-evaluated because most clinical guidelines were established based on data obtained from Western patient cohorts where a significant number of indolent RAS-like tumors were misclassified in the malignant category.

The case report details the first glomus tumor (GT) of uncertain malignant potential within the cervical spine. The patient had been experiencing neck pain and numbness of the left side of her body for 3 months. Magnetic resonance imaging (MRI) revealed a lesion with the dimensions 22 mm × 11 mm in the left side of the intervertebral foramen and epidural of C1-5. When the patient appeared aggravating symptoms, we performed an emergency surgery to relieve the spinal cord compression resulting from the growing tumor. During the surgery, a grey-brown friable tumor was observed, and the tumor was located both outside and inside of the cervical spine. Morphological and immunohistochemical (IHC) analysis showed that the lesion was a globular tumor with uncertain malignant potential. After the surgery, the patient received adjuvant radiotherapy consisting of 58.9 Gy in 23 fractions postoperatively. The MRI at 4 months after the surgery showed a progression of the tumor, at which point the patient ceased treatment. GT of uncertain malignant potential within the cervical spine lacks specific clinical manifestations and reliable non-invasive means of examination, so its diagnosis depends on pathological biopsy and IHC examination. Surgical excision is the first treatment to relieve the symptoms of nerve compression. Further research of postoperative radiotherapy and chemotherapy is required to improve treatment options.

Prostatic stromal tumor of uncertain malignant potential (STUMP), characterized by an atypical, unique stromal proliferation of the prostate, is often difficult to be differentiated from other nonepithelial neoplastic lesions. We present a unique case of recurrent STUMP after transurethral resection of the prostate (TURP) with concurrent prostatic adenocarcinoma. Patients diagnosed with prostatic STUMP should be followed up closely, for it may recur and invade adjacent organs after TURP shortly. Concurrent prostatic adenocarcinoma can be found in STUMP patients, and there may be some potential mechanisms which promote the simultaneous occurrence of the 2 tumors.