PNL2: A Useful Adjunct Biomarker to HMB45 in the Diagnosis of Uterine Perivascular Epithelioid Cell Tumor (PEComa).

Perivascular epithelioid cell tumors (PEComa) are rare neoplasms characterized by co-expression of melanocytic and muscle markers. HMB45 and Melan-A are used to confirm a PEComa diagnosis; however, both are often focally expressed and sensitivity for Melan-A is low. PNL2 is a reliable biomarker for epithelioid melanoma and renal angiomyolipoma/PEComa. The objective of this study was to determine PNL2 utility in diagnosing uterine PEComas as well as distinguishing PEComas from uterine smooth muscle tumors (SMTs). Twenty-one uterine PEComas and 45 SMTs were analyzed for PNL2; a subset was also stained for HMB45, Melan-A, Cathepsin-K, Desmin, and h-Caldesmon. Cases were scored as negative (0), focal (<10% of tumor cells), or patchy to diffusely positive (>10% of tumor cells). PEComas were positive for PNL2, HMB45, and Melan-A in 86%, 100%, and 57% of cases, respectively. In PEComas, PNL2 was patchy to diffusely positive more frequently (10/18, 56%) than Melan-A (4/12, 33%). In contrast, 2 of 45 (4%) SMTs were focally PNL2 positive; HMB45 was focally positive in 4 SMTs (11%) and all were negative for Melan-A. Desmin and h-Caldesmon were positive in 90% and 57% of PEComas, and 91% and 82% of SMTs. Cathepsin-K was positive in 100% of PEComas and 93% of SMTs. PNL2 is a useful biomarker for the diagnosis of uterine PEComa, with comparable sensitivity and specificity to HMB45. In contrast, PNL2 stains more PEComas when compared with Melan-A. Cathepsin-K, Desmin, and h-Caldesmon are of little utility for distinguishing PEComas and SMTs; however, lack of Cathepsin-K argues against PEComa. These results suggest that PNL2 should be used in conjunction with HMB45 in the diagnosis of PEComa of the uterine corpus.

Fusion of the HMGA2 and C9orf92 genes in myolipoma with t(9;12)(p22;q14).

BACKGROUND: Myolipoma of soft tissue is an extremely rare benign tumor composed of mature adipose tissue and smooth muscle cells. It is found predominantly in women. The cytogenetic and molecular genetic features of myolipomas remain largely unexplored. Here we present the first cytogenetically analyzed myolipoma. METHODS: Cytogenetic and molecular genetic analyses were done on a myolipoma. RESULTS: G-banding analysis of short-term cultured cells from the myolipoma yielded a karyotype with a single clonal chromosome abnormality: 46,XX,t(9;12)(p22;q14). Fluorescence in situ hybridization experiments demonstrated that HMGA2 (in 12q14) was rearranged. Molecular genetic analysis showed that the translocation resulted in fusion of HMGA2 with the C9orf92 gene (from 9p22). The HMGA2-C9orf92 fusion transcript would code for a putative protein containing amino acid residues 1-94 of HMGA2 and 6 amino acid residues from the out-of-frame fusion with exon 4 of C9orf92. CONCLUSION: The pattern of HMGA2 rearrangement in the present case of myolipoma is similar to what is found in other benign connective tissue tumor types, including lipomas, i.e., disruption of the HMGA2 locus leaves intact exons which encode the AT-hook domains but separates them from the 3´-terminal part of the gene. Whether any genetic features differentiate myolipomas from regular lipomas with HMGA2-involvement is a question that cannot be answered until more cases of the former tumor type are subjected to genetic analysis.

[Smooth muscle tumor of uncertain malignant potential (STUMP)--clinico-pathomorphological analysis of the cases and literature review]. / Guz gladkomiesniowy o nieokreslonym potencjale zlosliwosci (STUMP)--analiza kliniczno-patomorfologiczna przypadków oraz przeglad pismiennictwa.

OBJECTIVES: This retrospective study was designed to evaluate the clinical and pathological features and outcomes of patients diagnosed with uterine smooth muscle tumor of uncertain malignant potential (STUMP). MATERIAL AND METHODS: Ten patients diagnosed with uterine STUMP and seen between 2008 and 2011 at the Memorial Cancer Center--Institute of Oncology in Warsaw were identified using the institution databases. Variables of interest included histopathological details, age at diagnosis, types of treatment and recurrence rate. RESULTS: The mean age at diagnosis was 41 years (range 25-56 years). The mean follow-up time was 16 months (range 4-29 months). Diameter of the tumors ranged from 3 to 29 cm. Uterine bleeding was the second most frequent symptom observed in this cohort In three cases conservative procedure was performed, whereas in other patients hysterectomy was performed. No recurrence was observed during the follow-up period. In all tumors mitoses were less than 10 per 10/hpf, atypia of middle or severe type, and in 3 cases necrosis was observed. In half of the tumors expression of TP53 was found, and value of MIB 1 was estimated at 2-35%. CONCLUSIONS: STUMP should be diagnosed by experienced pathologists due to the fact that they are often misdiagnosed as leiomyosarcomas. Clinical behavior of these tumors allows to consider a conservative management in patients wishing to preserve fertility

[Absorption of iodofolic acids by the cells of malignant tumors].

The uptake of 125-iodine labeled 3' iodofolic acid (I*F) and 3' iodo, 5 formyl tetrahydrofolic acid (I*FT) by the cells HeLa, ECV, L-41, human glioma, and rat glioma was studied. Human Embrionic Lung Fibroblasts (HELF) were taken for comparison as healthy cells. It was shown for *IF that its long-term uptake by cells L-41 and ECV is hundreds oftimes higher than those of HELF cells. The short-term uptake phase was studied for *IFT uptake. The dissociation constant was determined for a complex formed by *IFT and an acceptor in the HeLa cells, which is supposed to cause concentrative uptake of *IFT in cells. The dissociation constants of this acceptor complexes with folic acid, 3' iodofolic acid and 3',5'-diiodofolic acid were determined by competition with I*FT. The distribution ratio of *IF and *IFT in tissues of different organs of healthy mice and rats and rats with a sarcoma grafted on his thigh and glioma grafted into the brain was studied. As was shown there are large differences in the concentration of *IF and *IFT in the tumor and in the healthy tissue, *IF concentration in thigh muscle of healthy being 5 times lower than those in tumor grafted to the thigh, and *IFT concentration in healthy brain being 10 times lower than in brain tumor.

Synchronous hepatic, mesenteric and pulmonary Epstein-Barr virus-associated smooth muscle tumors in a renal transplant recipient.

Epstein-Barr virus-associated smooth muscle tumors (EBV-SMT) are distinct lesions that occur in immunocompromised patients. EBV-SMT following solid organ transplantation are rare and generally have an indolent biological behavior. Post-transplant EBV-SMT have been reported in various anatomical locations. This report describes a synchronous and multicentric development of EBV-SMT in liver, mesentery, and lung of a 33-yr-old male patient, 10 yr after a deceased allograft renal transplantation. The hepatic and mesenteric tumors were available for study. These tumors were composed of bland looking, desmin-positive, spindle-shaped cells which showed a strong nuclear staining for EBV with in situ hybridization technique. A literature review of post solid organ transplant EBV-SMT in the liver and lung, particularly regarding their pathogenesis, synchronicity and biological behavior would be provided.

Smoothelin is a specific marker for smooth muscle neoplasms of the gastrointestinal tract.

Smoothelin is a smooth muscle-specific cytoskeletal protein exclusively found in differentiated smooth muscle cells. This contrasts with other smooth muscle proteins (eg, h-caldesmon, alpha-smooth muscle actin, desmin, smooth muscle myosin), which are expressed in proliferative (early) stages of smooth muscle development and occasionally in other cell types (striated muscle, myofibroblasts, myoepithelial cells, pericytes). Smoothelin has been shown to be expressed predominantly in visceral smooth muscle and to a lesser extent in vascular smooth muscle. Smoothelin expression in mesenchymal tumors of the gastrointestinal (GI) tract has not been evaluated earlier. The purpose of this study was to determine whether immunostaining for smoothelin could help distinguish smooth muscle neoplasms from their morphologic mimics, particularly KIT-negative gastrointestinal stromal tumors (GISTs), desmin-positive GISTs, and desmoid fibromatosis. A total of 150 mesenchymal neoplasms of the GI tract, abdominal cavity, and retroperitoneum were retrieved from consult and surgical pathology archives, including 54 GISTs (8 KIT-negative; 13 desmin-positive), 17 GI leiomyosarcomas (LMS), 11 GI mural leiomyomas, 13 leiomyomas of the muscularis mucosae, 12 gastric schwannomas, 15 inflammatory myofibroblastic tumors, 9 cases of mesenteric desmoid fibromatosis, 10 dedifferentiated liposarcomas, and 9 malignant peripheral nerve sheath tumors. Immunostaining for smoothelin was performed on all cases. Cytoplasmic and nuclear staining was recorded. Cytoplasmic expression of smoothelin was present in all 24 (100%) benign smooth muscle tumors (mural leiomyomas and leiomyomas of the muscularis mucosae). In contrast, only 4 (24%) GI LMS showed cytoplasmic staining for smoothelin. None of the GISTs, desmoid tumors, inflammatory myofibroblastic tumors, schwannomas, dedifferentiated liposarcomas, or malignant peripheral nerve sheath tumors showed cytoplasmic reactivity for smoothelin. Interestingly, 7 (41%) GI LMS and 12 (22%) GISTs (all except 2 with an epithelioid component) showed multifocal, exclusively nuclear staining for smoothelin. Nuclear expression of smoothelin was not detected in any of the other tumor types examined. In summary, diffuse cytoplasmic staining for smoothelin is highly sensitive and specific for benign leiomyomas of the GI tract. Aberrant nuclear expression is common in GI LMS and may also be seen in GISTs, especially epithelioid and mixed-type tumors. These findings suggest that the extent and pattern of smoothelin expression may help differentiate between benign and malignant mesenchymal tumors of the GI tract, and may be useful in distinguishing leiomyomas from KIT-negative and/or desmin-positive GISTs.

Expression of cyclooxygenase-2, c-kit, progesterone and estrogen receptors in uterine smooth muscle tumors: differential diagnosis.

We examined the expression pattern of cyclooxygenase-2 (COX-2) and c-kit in uterine smooth muscle neoplasms and tried to determine the role of these markers in differential diagnosis. Archival tissue from 64 patients with uterine smooth muscle neoplasms (20 leiomyomas (LMs), 22 atypical leiomyomas (ALMs), and 22 leiomyosarcomas (LMSs)) was immunostained with antibodies against estrogen (ER) and progesterone receptors (PR), COX-2 and c-kit. 7 of 20 LM cases and 5 of 22 ALM cases were immunopositive for COX-2, whereas none of the LMS cases stained immunopositive (p< or =0.05). 4 of 20 LM cases and 5 of 22 ALM cases were immunopositive for c-kit, whereas 15 of 22 LMS cases showed c-kit immunopositivity (p< or =0.05). In conclusion, very few LMs and ALMs show COX-2 immunopositivity. LMSs usually do not express COX-2. COX-2 expression in smooth muscle tumors is not a prominent feature. Therefore, COX-2 inhibitors may not be useful in LMS therapy. C-kit was significantly expressed in uterine LMSs.

Diffuse intra-abdominal clear cell myomelanocytic tumor: report of an unusual presentation of "PEComatosis" simulating peritoneal mesothelioma.

We report a case of diffuse myomelanocytic tumor of the peritoneum that simulates, clinically and instrumentally, a malignant mesothelioma. The patient was a 70-year-old woman with a history of ancient hysterectomy for fibroids, who presented with abdominal discomfort. Exploratory laparotomy revealed diffuse encasing of the peritonealized organs by a thin, fleshy, gray-white tissue rind. Scattered tumor masses were present as well. A dominant lesion measuring 6 cm in larger size was resected from the pelvis. Histological examination revealed a tumor composed of epithelioid and spindle cells, exhibiting either a clear or slightly eosinophilic cytoplasm and a mild to moderate nuclear pleomorphism. Focal areas of necrosis could be documented. Immunohistochemically, tumor cells were positive for HMB45, melan-A, and smooth muscle actin, but negative for other antibodies, including epithelial markers, desmin, and S100 protein. We believe that this case represents an example of myomelanocytic tumor of uncertain biologic potential, a member of the recently devised perivascular epithelioid cell tumors (PEComa), with an unusual presentation simulating a diffuse mesothelial neoplasm. The origin of this particular lesion is briefly discussed in light of the recent literature published on the subject.

Cotyledonoid dissecting leiomyoma of the uterus: a case report of a benign uterine tumor with sarcomalike gross appearance and review of literature.

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.

Clear cell myomelanocytic tumor (PEComa) of the duodenum in a child with a history of neuroblastoma.

We report herein a case of digestive clear cell myomelanocytic tumor (PEComa) that is unique in its location and presentation. The lesion, located in the duodenal wall, was diagnosed in a child with a history of cervical neuroblastoma that was in remission after surgical resection and chemotherapy. The diagnosis was obtained by examination of a biopsy specimen taken during laparoscopy. The decision was made to perform surgical resection. Examination of the surgical specimen confirmed the diagnosis of PEComa. No metastasis was found. After 2 years of follow-up, the patient is alive, without evidence of metastasis or recurrence. This case highlights the distinctive characteristics of the cells in PEComa, recognizable even on limited biopsy material. It also suggests a possible association between PEComa and neuroblastoma, 2 unusual tumors that belong to the spectrum of lesions known to occur in patients with tuberous sclerosis and that may share a possible common pathogenetic mechanism.

Molecular pathogenesis of uterine smooth muscle tumors from transcriptional profiling.

Uterine smooth muscle tumors range from the very common benign leiomyoma to the uncommon, but frequently lethal, leiomyosarcoma. Morphological and clinical differences between these tumors are presumed to result from differences in gene expression. To test this hypothesis, RNAs from four normal uterine myometria, seven uterine leiomyomas, and nine uterine leiomyosarcomas were profiled using microarrays of oligonucleotides representing about 7,000 unique probe sets. RNAs whose levels distinguished any of the three sample types were selected by analysis of variance (ANOVA). The 153 (2.2% of the total) probe sets representing 146 unique genes with the highest test statistic selected for further analysis met minimum ratio and range thresholds between groups. Cluster analysis distinguished benign and malignant samples at the first node, and myometrium and leiomyoma were resolved in a secondary node. Downregulation of specific genes in uterine leiomyosarcoma was the most common pattern of differential gene expression selected by the three-way ANOVA. Four extrauterine leiomyosarcomas had profiles most similar to that of the uterine leiomyosarcomas. Functional analysis of the 146 genes did not reveal any strong biological theme. These genes were distributed throughout the genome, but there was slight overrepresentation of genes on 1p and 2q. These genes define a tumor signature for uterine smooth muscle neoplasia, and they suggest that the molecular pathways in leiomyoma and leiomyosarcoma are distinct.

Estrogen and progesterone receptor expression in patients with uterine smooth muscle tumors.

OBJECTIVE: To investigate the expression of estrogen and progesterone receptor in uterine leiomyomas, smooth muscle tumors of uncertain malignant potential (STUMP), and leiomyosarcomas (LMS), and to assess the correlation between steroid receptor expression and clinicopathologic parameters in LMS. DESIGN: Estrogen/progesterone receptor expression was investigated by immunohistochemistry. SETTING: Department of Gynecology and Obstetrics of the University Hospital of Vienna. PATIENT(S): Twenty-six women with leiomyoma, 24 with STUMP, and 21 with LMS of the uterus. INTERVENTION(S): Formalin-fixed, paraffin-embedded tissues were sectioned and stained. MAIN OUTCOME MEASURE(S): Number of tumor cells stained. RESULT(S): Significant differences regarding the frequency of estrogen receptor expression were observed between LMS and leiomyoma and STUMP and leiomyoma (P<.05). The progesterone receptor expression did significantly differ between LMS and STUMP (P=.05), and LMS and leiomyoma (P<.05). In uterine LMS, the relationship between estrogen/progesterone receptor expression and clinicopathologic parameters did not reach statistical significance (P>.05), and neither of the markers studied revealed prognostic significance (P>.05). CONCLUSION(S): The present study observed significant differences of steroid receptor expression between uterine leiomyoma, STUMP, and LMS. Our data indicate that the progesterone receptor may be an especially useful marker to distinguish cases of malignant smooth muscle tumors in which histological features are ambiguous or borderline.

Bcl-2 receptor expression in patients with uterine smooth muscle tumors: an immunohistochemical analysis comparing leiomyoma, uterine smooth muscle tumor of uncertain malignant potential, and leiomyosarcoma.

OBJECTIVE: Bcl-2 protein is an apoptosis-inhibiting gene product that prevents the normal course of apoptotic cell death in a variety of cells. Additionally, bcl-2 can promote cell replication by reducing the requirement for growth factors. This protein seems, therefore, to play an important role in the growth of tumors. Our aim was to investigate the different expression of bcl-2 in uterine leiomyomas, smooth muscle tumors of uncertain malignant potential (STUMP), and leiomyosarcomas (LMS). Furthermore, the correlation between bcl-2 expression and various clinicopathologic parameters in leiomyosarcomas was assessed to evaluate its prognostic value. METHODS: This study included 26 cases of leiomyoma, 22 cases of STUMP, and 21 cases of LMS of the uterus. Bcl-2 expression was investigated by immunohistochemistry from paraffin-embedded tissue. The immunohistochemical findings were compared and correlated with different clinicopathologic parameters. Clinical information, including follow-up data, was obtained from the database of the Department of Gynecology and Obstetrics. RESULTS: Bcl-2 was present in 12 of 21 LMS, eight of 22 STUMP, and 20 of 25 leiomyomas. Significant differences regarding the frequency of bcl-2 expression and the staining intensity were observed between LMS and leiomyoma as well as between STUMP and leiomyoma (P <.05) but not between LMS and STUMP (P >.05). Regarding the outcome of uterine LMS, patients with bcl-2 positive tumors showed less vascular space involvement and longer overall survival (P <.05). CONCLUSION: Bcl-2 was expressed more frequently and more strongly in leiomyomas compared with LMS and STUMP. Regarding the outcome of uterine LMS, patients with bcl-2-positive tumors showed less vascular space involvement and longer overall survival. The stronger bcl-2 expression in benign leiomyomas and the better clinical outcome of bcl-2-positive LMS indicate that this protein seems to act as a good prognostic factor. Further studies including larger numbers of patients are necessary to establish bcl-2 as a routine marker for improved prognosis in malignant uterine smooth muscle tumors.

Do leiomyomas of deep soft tissue exist? An analysis of highly differentiated smooth muscle tumors of deep soft tissue supporting two distinct subtypes.

There is a prevailing view that leiomyomas of deep soft tissue are rare or nonexistent, but there are limited data on this subject in the form of large clinical studies with long follow-up information. We reviewed 36 consultation cases that had been diagnosed as leiomyoma or probable leiomyoma based on absence of nuclear atypia, necrosis, and no/minimal mitotic activity. Follow-up information was obtained to determine whether these stringent histologic criteria could identify a biologically benign group of smooth muscle tumors of deep soft tissue. The tumors occurred in two distinct locations. The first (n = 13) occurred in deep somatic soft tissue of the lower extremity (7), upper extremity (2), trunk (2), axilla (1), and back (1) and affected the sexes equally (7 male, 6 female). Composed of a circumscribed mass of mature smooth muscle cells, they were frequently calcified with a mean mitotic activity of <1 mitosis/50 high power fields (HPF) (range 1-4 mitoses/50 HPF). Estrogen receptor and progesterone receptor proteins were negative in the three cases tested. No tumors recurred or metastasized (mean follow-up 58.7 months, range 5-97 months). The second group (n = 23) occurred within the retroperitoneum (20) or abdominal cavity (3) of women (1 male, 22 female). Resembling uterine leiomyomas, they were always distinct from the uterus, occasionally multiple (n = 4), and sometimes occurred up to years after hysterectomy (n = 3). Four cases occurred with synchronous uterine leiomyomas. In the six cases tested, five of six were positive for the estrogen receptor protein and all were positive for progesterone receptor protein. Mean mitotic activity was 1 mitosis/50 HPF (range <1-10 mitoses/50 HPF). None developed metastasis within the follow-up period (mean 42.5 months, range 6-120 months); one tumor with a positive margin recurred at 10 months. We conclude that clinically benign smooth muscle tumors of deep soft tissue are rare but can be identified using stringent histologic criteria. They comprise two distinct subtypes: leiomyomas of somatic soft tissue and retroperitoneal-abdominal leiomyomas. The latter probably arise from hormonally sensitive smooth muscle. Although similar to uterine leiomyomas, they are located at sites removed from the uterus and are likely independent soft tissue primaries rather than parasitic leiomyomas of the uterus. We suggest that these two groups of smooth muscle tumors be diagnostically approached in a site-specific fashion.

Multiple smooth muscle tumors arising in deep soft tissue of lower limbs with uterine leiomyomas.

A 40-year-old woman had multiple smooth muscle tumors in the left inguinal region, the bilateral thighs, the omentum, the peritoneum, and the right infundibulum pelvic ligament associated with uterine leiomyomas. She had a history of uterine leiomyomas, which were resected 13 years ago. Histopathologic evaluation revealed tumor masses composed of smooth muscle cells with relatively low cellularity, which were consistent with a diagnosis of leiomyoma. Tumor necrosis and nuclear atypia were absent. Mitotic figures were very scarce (less than 1 mitotic figure per 10 high-power fields). Immunohistochemical evaluation revealed a positive reaction of the tumor cells to muscle markers, estrogen receptors, and progesterone receptors. No pulmonary lesion was found. Similar instances of uterine leiomyomas with histologically benign extrauterine smooth muscle tumors have been reported. This curious condition has been referred to as "benign metastasizing leiomyoma," in which most of the reported cases involve the lungs. The distribution of extrauterine tumors in our case is very unusual and may be the first case with multiple leiomyomas in deep soft tissue of the limbs. Consideration was given to the concept that these may be of multifocal origin, rather than metastases.

[Smooth muscle neoplasms of the uterus--a 51 cases study].

To discuss the diagnosis of uterine leiomyosarcoma and leiomyoma of cellular and bizarre type, we reviewed 51 cases and carried out P53 and desmin immunohistochemical staining on 43 cases. We found that in most cases leiomyosarcoma is accompanied by nuclear mitosis, cell atypia and margin infiltration. In a small number of cases, though mitotic figures are scarce, high cell atypia and marked margin infiltration were present. Leiomyoma variants may have high cellular density and bizarre nuclears but have no margin infiltration. Leiomyosarcoma has a high incidence of P53 expression, while no P53 expression was detected in leiomyoma variants. Desmin expression is closely correlated with the differentiation of smooth muscle neoplasms of the uterus. We conclude that nuclear mitotic activity is an important but not independent criteria in the diagnosis of uterine leiomyosarcoma. Cellular atypia and margin infiltration should be considered. P53 and desmin expression can be applied as accessary criteria.