Smooth muscle tumors of uncertain malignant potential and leiomyosarcomas of the uterus: MR findings

PURPOSE

To study the MR characteristics of nonbenign uterine smooth muscle tumors.

MATERIALS AND METHODS

Nine patients with pathologically proven leiomyosarcomas, and three patients with smooth muscle tumors of uncertain malignant potential (SMTUMP) were included in this study. Twelve cases of benign uterine leiomyomas and variants, in which gynecologists suspected leiomyosarcomas, were also analyzed. In each case we studied the size, location, signal intensity, and contrast enhancement of the tumors.

RESULTS

Nine of the 12 nonbenign characters had more than 50% of high-intensity areas on T2-weighted images (T2WI), and some hyperintense foci on T1-weighted images (T1WI). In the contrast study, nine of 12 nonbenign characters had well-demarcated unenhanced areas. On the other hand, only two of 12 benign characters showed such a signal intensity pattern, and none of them had a pocket-like unenhanced area.

CONCLUSION

Although there were some exceptions, more than 50% of high signal on T2WI, and the presence of any small high-signal areas on T1WI with unenhanced pockets were considered MR-suggestive for SMTUMPs and leiomyosarcomas.

h-Caldesmon in leiomyosarcoma and tumors with smooth muscle cell-like differentiation: its specific expression in the smooth muscle cell tumor

h-Caldesmon (h-CD) is a protein combined with actin and tropomyosin that regulates cellular contraction. h-CD has been thought to be expressed exclusively in vascular and visceral smooth muscle cells (SMC). We examined h-CD expression immunohistochemically in tumors with SMC and SMC-like differentiation to clarify whether h-CD is specifically expressed in SMC tumors. The tumors examined in this study were six leiomyomas (LM), two angioleiomyomas (ALM), six leiomyosarcomas (LMS), eight rhabdomyosarcomas (RMS), eight malignant fibrous histiocytomas (MFH), four desmoids, three glomus tumors (GT), and two inflammatory myofibroblastic pseudotumors (IMP) of urinary bladder. We found that LM, ALM, LMS, and GT showed intense and extensive immunoreactivity for h-CD, whereas other tumors were completely negative for h-CD. In addition, h-CD was not present in the vascular pericytes and myofibroblasts, in contrast to actin. Although myoepithelial cells were immunopositive for h-CD, neoplastic myoepithelial cells of myoepithelial tumors and mixed tumors of the salivary gland and skin were all negative. These findings indicate that h-CD is a specific marker of both SMC and its neoplasms and that immunohistochemical detection of h-CD may facilitate the differential diagnosis between LMS and other tumors with SMC-like differentiation, including myofibroblastic tumors.

Malignant smooth muscle tumors presenting as mediastinal soft tissue masses. A clinicopathologic study of 10 cases

BACKGROUND

Smooth muscle tumors presenting as mediastinal soft tissue masses are extremely rare and often are mistaken for other neoplastic conditions.

METHODS

Ten cases of patients with malignant smooth muscle tumors presenting as mediastinal soft tissue masses were studied and correlated with their clinical behavior. Tissues were examined histologically and with immunohistochemical stains in all cases, and by electron microscopy in two cases.

RESULTS

The patients' ages ranged from 26 to 71 years (mean, 56 years); three were women, and seven were men. Three cases were located in the anterior mediastinum and seven in the posterior mediastinum. The patients with anterosuperior mediastinal tumors all presented with signs and symptoms referable to their lesions; the patients with posterior mediastinal masses (with the exception of one) were all asymptomatic. Grossly, the lesions were well circumscribed and unencapsulated, ranging from 6 to 18 cm in greatest dimension and showed a homogeneous, rubbery cut surface with prominent cystic and myxoid areas. The tumors in all patients appeared to arise from the soft tissues within the mediastinum and were unrelated to adjacent structures. In three patients, the tumors compressed and displaced the esophagus without infiltrating its wall, and in one patient, the tumor was found in close proximity, although unattached, to a large vessel. Histologically, the lesions exhibited a spectrum of morphologic appearances that ranged from low grade leiomyosarcoma with mild-to-moderate nuclear atypia and low mitotic activity (< 3/10 high power fields [HPFs]), to high grade tumors with marked nuclear pleomorphism, extensive areas of necrosis, and high mitotic activity (> 10 mitoses/10 HPFs). One case was characterized by a striking epithelioid morphology with large, round cells arranged in small clusters; another was associated with an incidental microscopic focus of thymic seminoma in the adjacent thymus. Immunohistochemical stains in all cases showed positive labeling of the tumor cells with smooth muscle actin, desmin, and vimentin antibodies. Electron microscopy in two cases showed features of smooth muscle differentiation, i.e., spindle cells surrounded by basal lamina material, immature cell junctions, and abundant intracytoplasmic filaments with focal condensations. All patients were treated with surgical excision. On follow-up, three patients with Stage IIIb and IVa tumors died 2-7 years after surgery, and two patients with Stage Ib and IIb were alive and well 4 and 6 years after surgery, respectively.

CONCLUSION

Leiomyosarcomas may arise as primary tumors originating from mediastinal soft tissues in both anterior and posterior compartments. Because of their large size and frequent areas of cystic and myxoid degeneration, they may be confused histologically with neural or other neoplasms. As with their counterparts in other soft tissue locations, histologic grade and clinical stage are the most useful parameters for assessing prognosis.

Differential expression of smooth muscle myosin, smooth muscle actin, h-caldesmon, and calponin in the diagnosis of myofibroblastic and smooth muscle lesions of skin and soft tissue

The diagnosis of low-grade and pseudosarcomatous spindle cell lesions of skin and soft tissue can sometimes be problematic; in particular, distinction between fibroblastic, myofibroblastic, and smooth muscle proliferations can occasionally pose difficulties on routine histologic examination. We have applied a panel of immunohistochemical markers to a series of spindle cell lesions of skin and soft tissue to assess the utility of the differential expression of smooth muscle and myofibroblastic-associated markers. Twenty-eight cases of nodular fasciitis, 42 cases of fibromatosis, and 3 cases of myofibroblastic sarcoma were stained with antibodies against smooth muscle actin (SMA), smooth muscle myosin (SMMS), calponin, and high-molecular weight caldesmon (h-caldesmon). For comparison, 12 cases of cutaneous leiomyoma and 8 cases of leiomyosarcomas involving superficial soft tissues and fascia were studied with the same panel of antibodies. Thirty-eight of 42 cases of fibromatosis were positive for SMA, 42/42 cases were positive for calponin, 39/42 cases were negative for SMMS, and all cases were negative for h-caldesmon. All cases of nodular fasciitis were positive for SMA and calponin, and all were negative for h-caldesmon and SMMS. All cases of myofibroblastic sarcoma were positive for SMA and 2/3 cases for calponin, and were negative for SMMS and h-caldesmon. All cases of cutaneous leiomyoma and leiomyosarcoma were positive for all 4 markers tested. Our results demonstrate a remarkably consistent pattern of reactivity of muscle and myofibroblastic-associated markers in lesions predominantly composed of myofibroblastic spindle cells, characterized by positive staining for SMA and calponin and absence of reactivity for SMMS and h-caldesmon. Application of this panel of stains may be of aid in the differential diagnosis of low-grade myofibroblastic lesions such as nodular fasciitis and fibromatosis from smooth muscle tumors of skin and soft tissue. This panel may additionally be of assistance in the diagnosis of myofibroblastic sarcoma.

Uterine smooth-muscle tumors with unusual growth patterns: imaging with pathologic correlation

OBJECTIVE

This essay illustrates the salient features of variant smooth-muscle tumors on multiple imaging techniques with correlative pathology. We describe how recognition of these features allows the radiologist to distinguish a uterine leiomyoma variant from the classic fibroid or a leiomyosarcoma. Finally, we highlight the role of the radiologist in triaging these patients to surgical versus medical management and in surgical planning.

CONCLUSION

Parasitic leiomyoma, intravenous leiomyomatosis, disseminated peritoneal leiomyomatosis, and benign metastasizing leiomyoma show key features on multiple imaging techniques that correlate with pathology findings. In the appropriate clinical setting, the radiologist should include these unusual lesions in the broader differential diagnosis of smooth-muscle tumors and, in certain cases, aid in surgical planning.

Malignant perivascular epithelioid cell tumor involving the prostate

Perivascular epithelioid cell tumor (PEComa) is a neoplasm chiefly composed of HMB-45-positive epithelioid cells with clear-to-granular cytoplasm and a perivascular distribution. We describe such a tumor involving the prostate and seminal vesicle in a 46-year-old man. The tumor had characteristic histologic features of PEComa. Immunohistochemically, the tumor cells were positive for HMB-45 but negative for epithelial markers, Melan-A, and S100 protein. The tumor behaved in a malignant fashion, and the patient died of the disease 4 years after diagnosis.

Gastric smooth muscle tumors: diagnostic dilemmas and factors affecting outcome

We reviewed the 46 gastric stromal tumors that were treated at our institution between 1958 and 1992. The most common presenting symptoms were gastrointestinal bleeding, pain, and fatigue or malaise. The tumors ranged from 4 to 150 mm, with surgery most often being a wedge excision or partial gastrectomy. Abdominal computed tomography was the most specific diagnostic test obtained preoperatively. Factors associated with decreased survival included size >/= 8 cm (p = 0.02), more than 0-3 mitoses per 10 HPF (p < 0. 001), positive margins or unresectability (p = 0.008), and tumor pathologic grade II or more (p = 0.004). These tumors have an unpredictable behavior. Surgical resection with negative margins remains the best therapy, but resection for palliation is sometimes indicated as it can be associated with prolonged survival.

Uterine smooth muscle tumors of uncertain malignant potential: diagnostic challenges and therapeutic dilemmas. Report of 2 cases and review of the literature

Morphologically, there exist variants of uterine smooth muscle tumors that cannot be clearly interpreted and classified as benign or malignant. Because their behavior and clinical prognosis is also uncertain, the World Health Organization has termed these "smooth muscle tumors of uncertain malignant potential" (STUMP). Herein we describe 2 cases, present a review of the literature, and highlight the diagnostic challenges and therapeutic dilemmas associated with uterine STUMP in myomectomy specimens from women who wish to maintain or enhance their fertility. The clinical course of residual STUMP remains speculative.

Primary duodenal neoplasms: A retrospective clinico-pathological analysis

AIM: To analyze the clinico-pathological spectrum of primary duodenal neoplasms.

METHODS: A total of 55 primary duodenal neoplasms reported in the last 10 years after excluding ampullary and periampullary tumors were included in the study. Clinical details were noted and routine hematoxylin and eosin stained paraffin sections were studied for histological subtyping of the tumors.

RESULTS: On histopathological examination primary duodenal neoplasms were categorized as: epithelial tumor in 27 cases (49.0%) including 10 cases of adenoma, 15 cases of adenocarcinoma, and 2 cases of Brunner gland adenoma; mesenchymal tumor in 9 cases (16.3%) consisting of 4 cases of gastrointestinal stromal tumor, 4 cases of smooth muscle tumor and I case of neurofibroma; lymphoproliferative tumor in 12 cases (21.8%), and neuroendocrine tumor in 7 cases (12.7%).

CONCLUSION: Although non-ampullary/periampullary duodenal adenocarcinomas are rare, they constitute the largest group. Histopathological examination of primary duodenal tumors is important for correct histological subtyping.

Ki-67 expression in patients with uterine leiomyomas, uterine smooth muscle tumors of uncertain malignant potential (STUMP) and uterine leiomyosarcomas (LMS)

BACKGROUND

The aim of the current study was to evaluate the expression of Ki-67 in uterine smooth muscle tumors, comparing leiomyomas, uterine smooth muscle tumors of uncertain malignant potential (STUMP) and uterine leiomyosarcomas (LMS) and to prove the accuracy of a Ki-67 expression as a useful parameter in the diagnosis of LMS.

METHODS

Ki-67 was assessed using immunohistochemistry from paraffin-embedded tissue in 20 patients with uterine LMS, 22 cases of STUMP and 25 cases of leiomyomas.

RESULTS

Ki-67 was present in 10/20 (50%) LMS, in 0/22 (0%) STUMP and in 2/25 (8%) leiomyomas. Significant differences regarding the frequency of Ki-67 expression were observed between LMS and STUMP (p = 0.0001) as well as between LMS and leiomyomas (p = 0.002), but not between STUMP and leiomyomas (p = 0.491). Likewise, the staining intensity differed significantly between LMS and leiomyomas (p = 0.018) as well as between LMS and STUMP (p = 0.002), but not between STUMP and leiomyomas (p = 0.368).

CONCLUSIONS

Our results demonstrate that the significantly elevated Ki-67 antigen expression in LMS, which correlates well with the rapid growth of these malignant tumors, may be a useful immunohistochemical parameter to distinguish between cases of malignant smooth muscle tumors and those of uncertain or borderline histology.

Epithelioid Leiomyosarcoma of the Uterus: Modern Outcome-based Appraisal of Diagnostic Criteria in a Large Institutional Series

Epithelioid leiomyosarcoma of the uterus is rare and poorly understood. Herein, we characterize a large institutional series of epithelioid leiomyosarcomas aiming to define outcome-determinant diagnostic pathologic features. We also retrieved epithelioid smooth muscle tumors of unknown malignant potential and evaluated a consecutive cohort of leiomyomas for epithelioid subtypes. Of a total of 1177 uterine leiomyosarcomas, 81 (7%) were categorized as epithelioid after review. Epithelioid leiomyosarcoma was strictly defined as having round to polygonal cells with visible pink cytoplasm and round to ovoid nuclei in ≥50% of the tumor volume. Average age was 55 years (range: 26 to 81 y). Median tumor size was 11 cm; tumor was >5 cm in 93% of subjects; 47% were stage 1 at presentation. An infiltrative tumor border was observed, grossly and/or microscopically, in 89% of cases; necrosis was noted in 80%, and vascular invasion in 47%. Mitotic count in 2.4 mm2 (totalling 10 high-power fields, each field 0.55 mm in diameter) ranged from 3 to 100 (median: 26). All cases had moderate, severe or highly pleomorphic atypia. All cases had 2 or 3 of the following: necrosis, at least moderate atypia and ≥4 mitoses in 2.4 mm2. Immunohistochemistry revealed frequent expression of smooth muscle markers including SMA (96%), desmin (95%), and caldesmon (81%). HMB45 and Melan-A were negative in 92% and 100% of cases, respectively. Estrogen and progesterone receptors were expressed by 65% and 54% of tumors, respectively. Follow-up information was available in 68 subjects (median: 23 mo, range: 1 to 254); cancer-related death occurred in 63%, and an additional 15% had recurrent or metastatic disease at last follow-up. Disease-specific survival was shorter in epithelioid leiomyosarcoma patients (median: 44  mo; 35% at 5-y) than in a matched cohort of nonepithelioid leiomyosarcoma (median: 55 mo; 46% at 5-y) (P=0.03). Three epithelioid smooth muscle tumors of unknown malignant potential were evaluated, all <5 cm in size and with atypia and/or irregular borders but mitotic count below the threshold for malignancy. Two of these had follow-up available, which was uneventful. Of 142 consecutive leiomyomas assessed, none had epithelioid morphology as defined. Epithelioid leiomyosarcoma is an aggressive neoplasm, sometimes with a remarkably low mitotic count. In the setting of an epithelioid smooth muscle tumor of the uterus, we postulate that the diagnosis of malignancy is made in the presence of ≥2 of the following: moderate or severe atypia, ≥4 mitoses/2.4 mm2 and tumor cell necrosis. In their absence, the finding of tumor size ≥5 cm, vascular invasion, infiltrative edges or atypical mitoses should be treated with caution, and designation as of at least uncertain malignant potential is warranted.

Differential Diagnosis of Smooth Muscle Tumors Utilizing p53, pTEN and Ki-67 Expression with Estrogen and Progesterone Receptors

BACKGROUND/AIM

To investigate the expression and value for diagnosis of the genes, p53 and pTEN, the protein, Ki-67, and the receptors, estrogen and progesterone, in differentiating smooth muscle tumors of the uterus.

MATERIAL AND METHOD

Seventeen samples of leiomyosarcoma, 2 smooth muscle tumors with uncertain malignant potential (STUMP), 9 atypical myomas and 15 leiomyomas were stained immunohistochemically. The chi(2) test was used for the statistical analysis of the data.

RESULTS

The malignant side of the spectrum was strongly stained for Ki-67 and p53 while uniformly decreasing toward the benign tumors. The results were found to be statistically significant (p < 0.0001). The staining for progesterone receptor was also statistically significant, but the tumors that were considered benign, such as leiomyoma and atypical myoma, were the ones strongly stained (p = 0.005). The expression of estrogen receptor was significant in these tumors, but the p value was very close to the cut-off value (p = 0.07). As the degree of differentiation of the tumor increased, the trend showed stronger staining for estrogen receptor. However, no difference was detected in the staining properties of the tumors for pTEN (p = 0.2457).

CONCLUSION

The expression of Ki-67, p53 and progesterone receptors is promising in immunodifferentiation of smooth muscle tumors of the uterus with malignant potential.

Cotyledonoid Dissecting Leiomyoma of the Uterus

Cotyledonoid dissecting leiomyoma (Sternberg tumor) is a very rare variant of uterine smooth muscle tumor with an unusual and alarming gross appearance. Including our case, approximately 20 cases were reported in the literature. A 27-year-old woman presented with pelvic mass. A 41-cm fungating rubbery mass with placenta-like appearance adhering to the posterior uterine surface and extending to the left broad ligament and pelvic cavity was observed. An intraoperative frozen section was requested, and a diagnosis of a benign smooth muscle tumor was given. Total abdominal hysterectomy and bilateral salpingo-oophorectomy were performed with removal of the pelvic tumor extension. Thorough tumor sampling was performed and showed nodules of interlacing bundles of bland-looking smooth muscle cells, separated by expanded, edematous, and highly vascularized stroma. No atypia, mitotic activity, or coagulative necrosis was seen. Immunohistochemical studies confirmed the smooth muscle nature of the tumor. Cotyledonoid leiomyoma has a distinctive gross appearance which usually raises the suspicion of sarcoma. Intraoperative frozen section is a mandatory and helpful procedure to avoid overtreatment of such cases.

Clinical update of smooth muscle tumors of the uterus

Smooth muscle tumors of the uterus represent a spectrum of diseases that range from benign leiomyoma to malignant leiomyosarcoma. The leiomyoma is the most common of these neoplasms. Clinically, it is important to fully understand the differences in clinical presentation, biologic behavior, and management for patients with benign leiomyoma, smooth muscle tumors of uncertain malignant potential, and leiomyosarcoma. The goal of this review is to present the most recent information about common smooth muscle tumors of the uterus including their etiology, histopathology, radiographic and clinical presentations, and available treatment options.

Analysis of Allelic Loss as an Adjuvant Tool in Evaluation of Malignancy in Uterine Smooth Muscle Tumors

Uterine smooth muscle tumors of uncertain malignant potential (STUMPs) are difficult both from the diagnostic and patient management standpoint because they cannot be classified as benign or malignant by conventional histologic criteria. This study's aim was to determine the diagnostic utility of allelic imbalance (AI) analysis in uterine smooth muscle tumors. Using microdissection and genotyping, we tested 5 leiomyomas, 6 STUMPs, and 10 leiomyosarcomas with follow-up for AI across a panel of seven tumor suppressor genes (p16, p21, p53, VHL, XRCC3, RB, and NM-23). None of the 6 patients with STUMP experienced recurrent disease, whereas 8 of the 10 patients diagnosed with leiomyosarcoma died of disease at follow-up. The mean frequency of allelic loss (FAL) for leiomyomas (18%) was not significantly different from that of STUMPs (21%) (P = 1), whereas leiomyosarcomas displayed a significantly higher FAL (52%) than both leiomyomas (P = 0.001) and STUMPs (P = 0.002). Loss of NM-23, a reported tumor metastasis suppressor gene, was found only in leiomyosarcomas (5 of 9, or 56%), and 4 of 5 (80%) of these were the only cases that demonstrated distant metastases (P = 0.04). Additionally, an FAL of >50% correlated with both NM-23 loss (P = 0.008) and distant metastatic disease (P = 0.04). In conclusion, leiomyomas and STUMPs displayed similar mean FALs and all were clinically benign, whereas uterine leiomyosarcomas had significantly higher frequencies of allelic loss than both leiomyomas and STUMPs. Molecular profiling may thus provide a valuable tool in assessment of malignancy in uterine smooth muscle tumors. Additionally, NM-23 is a promising candidate gene for determination of metastatic potential in these tumors.

Bilateral smooth-muscle tumors of the adrenals in a child with AIDS

We report a case of bilateral smooth muscle tumors (SMT) involving the adrenal glands in an 11-year-old female with acquired immunodeficiency syndrome (AIDS). The SMT of the right adrenal gland extended into the inferior vena cava, producing a tumor thrombus.

Progressive approach to the cytologic diagnosis of retroperitoneal spindle cell tumors

OBJECTIVE

To assess the utility of fine needle aspiration biopsy (FNAB) in retroperitoneal spindle cell tumors with difficult tumor typing.

STUDY DESIGN

Thirty-six cases of spindle cell tumors of the retroperitoneum were studied. Cytological diagnoses were set progressively: first exclusively by morphologic criteria on routinely stained slides, and then with the aid of immunocytochemistry (ICC), electron microscopy (EM) and clinical data.

RESULTS

The morphologic diagnosis of benignity or malignancy was first made in double blind fashion by two researchers; it permitted an exact diagnosis in 31 cases (86%) by one examiner and 27 cases (75%) by the second. Using a progressive approach, benignity or malignancy was definitively determined in 35 cases (97%). As far as cytologic tumor typing is concerned, first it proved to be possible in 27 cases (75%) and then in 30 cases (83%) with the progressive approach.

CONCLUSION

FNAB proved to be a useful tool in the diagnosis of retroperitoneal spindle cell tumors. A progressive approach to cytopathologic diagnosis, correlating morphology with ICC and EM results and matching them with clinical data, permitted a better differential diagnosis between benign and malignant spindle cell tumors and increased the possibility of correct tumor typing.

Duodenal gangliocytic paraganglioma: a radiological-pathological correlation

Duodenal gangliocytic paraganglioma is a rare tumor that characteristically occurs in the second portion of the duodenum and typically presents with gastrointestinal bleeding. Gangliocytic paragangliomas have a characteristic triphasic microscopic appearance with epithelioid cells, spindle cells, and ganglion cells, resulting in a complex histology with features of paraganglioma, carcinoid, and ganglioneuroma. Duodenal gangliocytic paragangliomas have an excellent prognosis after surgical resection but metastatic spread to regional lymph nodes and recurrence may rarely occur. We report a case of duodenal gangliocytic paraganglioma and discuss the radiological and pathological differential diagnosis of this rare entity.

Resolution of Multifocal Epstein-Barr Virus-Related Smooth Muscle Tumor in a Patient with GATA2 Deficiency Following Hematopoietic Stem Cell Transplantation

We performed allogeneic hematopoietic stem cell transplantation in a patient with GATA2 deficiency and an Epstein-Barr virus (EBV)-related spindle cell tumor involving the liver and possibly bone. He received a matched-related donor transplant with donor peripheral blood stem cells following a myeloablative conditioning regimen. He achieved rapid and high levels of donor engraftment and had complete reversal of the clinical and immunologic phenotype of MonoMAC/GATA2 deficiency and eradication of the EBV tumors after 3 years of follow-up. Thus, allogeneic hematopoietic stem cell transplant results in reconstitution of immunologic function and cure of EBV-associated malignancy in MonoMAC/GATA2 deficiency.

Incidental Stromal-Predominant Mixed Epithelial-Stromal Tumors of the Kidney: A Mimic of Intraparenchymal Renal Leiomyoma

Context.—Mixed epithelial-stromal tumor of the kidney is a recently recognized benign renal tumor that usually occurs in adult women and typically forms a sizable lesion with solid and cystic areas. The recognized morphologic spectrum of this recently described entity is evolving.

Objective.—To review the clinicopathologic features of 3 small mixed epithelial-stromal tumors of the kidney that were incidental findings in kidneys removed for other reasons.

Design.—The clinical presentation and morphologic findings of the 3 cases were reviewed. A panel of immunohistochemical stains was performed.

Setting.—Academic medical center.

Results.—All 3 lesions contained predominantly fascicles of smooth muscle mimicking leiomyoma, but they also had cellular subpopulations of smaller, müllerian-appearing stromal cells. Tubules present within the lesion were most abundant at the periphery, suggesting that they might be entrapped. Although only the spindled smooth muscle cells were immunoreactive for muscle markers desmin and actin, both the spindled smooth muscle cells and the cellular müllerian-appearing stromal cells demonstrated diffuse nuclear labeling for estrogen and progesterone receptors.

Conclusions.—Mixed epithelial-stromal tumor of the kidney may present as an incidental stromal-predominant lesion within the kidney. Such lesions are easily confused with leiomyomas or stromal-predominant angiomyolipomas.

Methodological aspects of using decision trees to characterise leiomyomatous tumors

The aim of the present work is to present the potential uses of a classification technique labeled the "decision tree" for tumor characterisation when faced with a large number of features. The decision tree technique enables multifeature logical classification rules to be produced by determining discriminatory values for each feature selected. In this report, we propose a methodology that used decision trees to compare and evaluate the information contributed by different types of features for tumor characterisation. This methodology is able to produce a set of hypotheses related to a diagnosis and or prognosis problem. For example, hypotheses can be producted (on the basis of a set of descriptive features) to explain why tumor cases belong to a given histopathological group. To illustrate our purpose, this methodology was applied to the difficult problem of leiomyomatous tumour diagnosis. The aim was to illustrate what kind of diagnostic information can be extracted from a sample data set including 23 smooth muscle tumors (14 benign leiomyomas and 9 malignant leiomyosarcomas) described by a large set of computer-assisted, microscope-generated features. Three groups of features were used relating to: (1) ploidy level determination (10 features), (2) quantitative chromatin pattern description (15 features), and (3) immunohistochemically related antigen specificities (6 features). All these features were quantified by digital cell image analysis. The results suggest that an objective distinction between leiomyomas and leiomyosarcomas can be established by means of simple logical rules depending on only a few features among which the immunohistochemically revealed antigen expression of desmin plays a preponderant part. One of the combinations of features proposed by the methodology is interesting for pathologists, because it includes two features describing the appearance of a nucleus in terms of chromatin distribution homogeneity and density, two features widely used by pathologists in tumor-grading systems.

Epstein-Barr virus-associated smooth muscle tumor presenting as a vulvar mass in an acquired immunodeficiency syndrome patient: a case report

Smooth muscle tumors in immunocompromised patients have a strong association with Epstein-Barr virus (EBV) infection. EBV-associated smooth muscle tumors (EBV-SMT) are considered as a distinct group of smooth muscle tumors with different clinicopathologic features from conventional smooth muscle tumors. A 31-year-old female patient presented with a 2-cm mass at the left labium majus, the clinical diagnosis of which was a Bartholin lesion. She had acquired immunodeficiency syndrome diagnosed 29 months before. Excisional biopsy revealed a cellular tumor composed of round- to spindle-shaped cells with mild to moderate nuclear atypia. The tumor cells were immunoreactive for smooth muscle actin and muscle actin (HHF-35). Evidence of EBV infection was confirmed by in situ hybridization for EBV-encoded small RNA-1. To our knowledge, this is the first case of EBV-SMT presenting as a vulvar mass. EBV-SMT should be included in the differential diagnoses of mesenchymal tumor in patients with immunosuppression and in the differential diagnoses of smooth muscle tumor in uncommon sites, including the vulva.

Endoscopic features of smooth muscle tumors in children with AIDS

BACKGROUND

Smooth muscle tumors are the second most common malignancy encountered in children with acquired immunodeficiency syndrome (AIDS). This study reviewed the incidence and endoscopic appearance of smooth muscle tumors in the gastrointestinal tract of children with AIDS undergoing endoscopy.

METHODS

Retrospective review of all endoscopic records (n = 70) of children with AIDS from August 1988 to December 1997 at a tertiary care inner city hospital.

RESULTS

Three children with advanced AIDS (4%) were found to have smooth muscle tumors, all of which had the typical appearance of submucosal nodules with central ulceration. Some were hemorrhagic. They measured less than 1 to 4 cm in diameter. Two children had multiple tumors. All lesions except for one were located in the colon. Colonic biopsies revealed a leiomyoma in one patient and a smooth muscle tumor of uncertain malignant potential in another. The forceps biopsy of the single gastric mass was not deep enough to make the diagnosis of a smooth muscle tumor. A nonmalignant smooth muscle tumor grew from less than 5 mm to more than 4 cm in 1 year and was removed surgically. All three children are alive without any evidence of local spread or distant metastases despite no specific therapy for the smooth muscle tumor.

CONCLUSIONS

Smooth muscle tumors in the GI tract of children with AIDS are relatively common. Further study of the long-term outcome for children infected with the human immunodeficiency virus who have these lesions are needed to establish prognosis and management guidelines.

Smooth Muscle Tumor of Uncertain Malignant Potential (STUMP): A Comprehensive Multidisciplinary Update

Background and Objectives: The uterine smooth muscle tumors of uncertain malignant potential (STUMP) are tumors with pathological characteristics similar to leiomyosarcoma, but that do not satisfy histological criteria for leiomyoma. These are problematic lesions with intermediate morphologic features; thus, diagnosis and treatment are difficult. This narrative review aims to review data in the literature about STUMPs, particularly focusing on management and therapeutic options and strategies for women who desire to preserve fertility. Material and Methods: authors searched for "uterine smooth muscle tumor of uncertain malignant potential" in PubMed and Scopus databases, from 2000 to March 2023. Pertinent articles were obtained in full-text format and screened for additional references. Only articles in English language were included. Studies including full case description of patients with histopathological diagnosis of STUMP in accordance with Stanford criteria were included. Results: The median age was 43 years old. Symptoms are similar to those of leiomyomas, with a mean diameter of 8.0 cm. Total hysterectomy with or without bilateral salpingo-oophorectomy is the standard care for women if fertility desire is satisfied. Myomectomy alone can be considered for young patients. Although these tumors have not a high malignant potential, several studies described recurrence and metastases. Conclusions: STUMPs are complex uterine smooth muscle tumors, with a rare but reasoned clinical-diagnostic management. Considering the high clinical and histological complexity of these tumors, high level of expertise is mandatory.