Expanding the Spectrum of NUTM1 -Rearranged Sarcoma : A Clinicopathologic and Molecular Genetic Study of 8 Cases.

Apart from the lethal midline carcinoma (NUT carcinoma), NUTM1 translocation has also been reported in mesenchymal tumors, but is exceedingly rare. Here, we describe a series of 8 NUTM1 -rearranged sarcomas to further characterize the clinicopathologic features of this emerging entity. This cohort included 2 males and 6 females with age ranging from 24 to 64 years (mean: 51 y; median: 56 y). Tumors occurred in the colon (2), abdomen (2), jejunum (1), esophagus (1), lung (1) and infraorbital region (1). At diagnosis, 6 patients presented with metastatic disease. Tumor size ranged from 1 to 10.5 cm (mean: 6 cm; median: 5.5 cm). Histologically, 4 tumors were composed of primitive small round cells to epithelioid cells intermixed with variable spindle cells, while 3 tumors consisted exclusively of small round cells to epithelioid cells and 1 tumor consisted predominantly of high-grade spindle cells. The neoplastic cells were arranged in solid sheets, nests, or intersecting fascicles. Mitotic activity ranged from 1 to 15/10 HPF (median: 5/10 HPF). Other features included rhabdoid phenotype (4/8), pronounced nuclear convolutions (2/8), prominent stromal hyalinization (2/8), focally myxoid stroma (1/8), foci of osteoclasts (1/8), and necrosis (1/8). By immunohistochemistry, all tumors showed diffuse and strong nuclear staining of NUT protein, with variable expression of pancytokeratin (AE1/AE3) (2/8), CK18 (1/8), CD99 (3/8), NKX2.2 (2/8), cyclin D1 (2/8), desmin (2/8), BCOR (2/8), S100 (1/8), TLE1 (1/8), and synaptophysin (1/8). Seven of 8 tumors demonstrated NUTM1 rearrangement by fluorescence in situ hybridization analysis. RNA-sequencing analysis identified MXD4::NUTM1 (3/7), MXI1::NUTM1 (3/7), and MGA::NUTM1 (1/7) fusions, respectively. DNA-based methylation profiling performed in 2 cases revealed distinct methylation cluster differing from those of NUT carcinoma and undifferentiated small round cell and spindle cell sarcomas. At follow-up (range: 4 to 24 mo), 1 patient experienced recurrence at 8.5 months, 4 patients were alive with metastatic disease (5, 10, 11, and 24 mo after diagnosis), 3 patients remained well with no signs of recurrence or metastasis (4, 6, and 12 mo after diagnosis). Our study further demonstrated that NUTM1 -rearranged sarcoma had a broad range of clinicopathologic spectrum. NUT immunohistochemistry should be included in the diagnostic approach of monotonous undifferentiated small round, epithelioid to high-grade spindle cell malignancies that difficult to classify by conventional means. DNA-based methylation profiling might provide a promising tool in the epigenetic classification of undifferentiated sarcomas.

Right atrial cardiac myxoma with malignant transformation to undifferentiated sarcoma: A case report.

Generally, sarcomas arising from benign soft tissue are rare. Cardiac myxoma (CM) is a benign tumor, and few reports have described its malignant transformation. Herein, we documented a case of an 89-year-old man with prostate cancer and a 5-year history of a right atrium tumor without Carney complex. The tumor was resected surgically and had a myxomatous or gelatinous appearance. Microscopically, the tumor had two components: a sarcomatous area and myxomatous area. In the myxomatous area, typical myxoma cells were demonstrable and were strongly immunoreactive for immunohistochemistry (IHC) of calretinin. In the sarcomatous area, the epithelioid- to spindle-shaped cells with prominent atypia proliferated densely. The IHC profile of cells in the sarcomatous area was different from that of cells in the myxomatous area; MDM2-positive cells were found only in the sarcomatous area. Especially, the Ki-67 index and number of p53-positive cells in the sarcomatous area were higher than those in the myxomatous area. The transition of the two components was seamless. Thus, we made a diagnosis of CM with malignant transformation corresponding to undifferentiated pleomorphic sarcomas. This case suggests that CM may transform into sarcoma, albeit rarely.

Myxoid Inflammatory Myofibroblastic Sarcoma: Clinicopathologic Analysis of 25 Cases of a Distinctive Sarcoma With Deceptively Bland Morphology and Aggressive Clinical Behavior.

The number of recognized sarcoma types harboring targetable molecular alterations continues to increase. Here we present 25 examples of a distinctive myofibroblastic tumor, provisionally termed "myxoid inflammatory myofibroblastic sarcoma," which might be related to inflammatory myofibroblastic tumor, and which occurred in 13 males (52%) and 12 females at a median age of 37 years (range: 7 to 79 years). Primary tumor sites were peritoneum (18 patients; 72%), paratesticular (2; 8%), chest wall (1), upper extremity (1), esophagus (1), retroperitoneum (1), and uterus (1). Nine peritoneal tumors (50%) were multifocal at presentation; all other tumors were unifocal. Tumors showed bland-to-mildly-atypical neoplastic myofibroblasts in a myxoid stroma, with prominent inflammatory infiltrates in 22 cases (88%). Most tumors showed delicate branching stromal vessels like those of myxoid liposarcoma, and most showed infiltrative growth through non-neoplastic tissue. Immunohistochemistry demonstrated expression of SMA (19/25 tumors; 76%), desmin (13/22; 59%), and CD30 (5/11; 45%), while ALK was expressed in 1 tumor (of 25; 4%) that was negative for ALK rearrangement. Sequencing of 11 tumors showed seven to harbor tyrosine kinase fusions (4 PDGFRB , 2 PML :: JAK1 , 1 SEC31A :: PDGFRA ). Two instead harbored hot spot KRAS mutations (G12V and Q61H), and 2 were negative for known driving alterations. Clinical follow-up was available for 18 patients (72%; median: 2.7 years; range: 4 mo-12.3 years). Nine patients (50%) were alive with no evidence of disease, 5 (28%) died of disease, and 4 (22%) were alive with disease. Seven patients (39%) experienced peritoneal relapse or distant metastasis. Two patients showed disease progression on conventional, nontargeted chemotherapy. The patient whose tumor harbored SEC31A :: PDGFRA was treated after multiple relapses with imatinib and sunitinib therapy, with progression-free periods of 5 and 2 years, respectively. Despite its bland appearance, myxoid inflammatory myofibroblastic sarcoma harbors a significant risk for disseminated disease, particularly when it occurs in the peritoneum. Targeted therapy could be considered for patients with disseminated disease.

GLI1 Immunohistochemistry Distinguishes Mesenchymal Neoplasms With GLI1 Alterations From Morphologic Mimics.

Glioma-associated oncogene 1 ( GLI1 ) alterations have been described in pericytoma with t(7;12), gastroblastoma, plexiform fibromyxoma, and an emerging class of GLI1 -rearranged or amplified mesenchymal neoplasms including "nested glomoid neoplasm". The immunophenotype of these tumor types is nonspecific, making some cases difficult to diagnose without sequencing. The utility of GLI1 immunohistochemistry (IHC) in distinguishing nested glomoid neoplasms and pericytomas with t(7;12) from morphologic mimics is unknown. To investigate the diagnostic value of GLI1 IHC, we determined its sensitivity and specificity in a "test cohort" of 23 mesenchymal neoplasms characterized by GLI1 alterations, including 12 nested glomoid neoplasms (7 GLI1 -rearranged, 4 GLI1 amplified, and 1 unknown GLI1 status), 9 pericytomas with t(7;12), 1 gastroblastoma, and 1 malignant epithelioid neoplasm with PTCH1 :: GLI1 fusion. GLI1 IHC was 91.3% sensitive in this cohort; all tumors except 2 pericytomas with t(7;12) expressed GLI1. GLI1 was also expressed in 1 of 8 (12%) plexiform fibromyxomas. Nineteen of 22 GLI1-positive tumors showed nuclear and cytoplasmic staining, while 3 showed nuclear staining only. GLI1 IHC was 98.0% specific; among morphologic mimics [40 well-differentiated neuroendocrine tumors, 10 atypical lung carcinoids, 20 paragangliomas, 20 glomus tumors, 20 solitary fibrous tumors, 10 Ewing sarcomas, 10 alveolar rhabdomyosarcomas (ARMS), 10 BCOR -altered sarcomas, 10 myoepitheliomas, 9 myopericytomas, 9 epithelioid schwannomas, 9 ossifying fibromyxoid tumors, 10 biphasic synovial sarcomas, 10 PEComas, 31 gastrointestinal stromal tumors, 10 inflammatory fibroid polyps, 11 pseudoendocrine sarcomas], 5 of 249 tumors expressed GLI1 (2 well-differentiated neuroendocrine tumors, 1 ARMS, 1 Ewing sarcoma, 1 BCOR -altered sarcoma). GLI1 IHC was also performed on a separate cohort of 13 molecularly characterized mesenchymal neoplasms in which GLI1 copy number gain was identified as a putatively secondary event by DNA sequencing (5 dedifferentiated liposarcoma [DDLPS], 2 adenosarcomas, 2 unclassified uterine sarcomas, 1 leiomyosarcoma, 1 ARMS, 1 intimal sarcoma, 1 osteosarcoma); 2 DDLPS, 1 ARMS, and 1 unclassified uterine sarcoma expressed GLI1. Lastly, because pleomorphic sarcomas sometimes show GLI1 amplification or copy number gain, GLI1 IHC was performed on a separate "pleomorphic sarcoma" cohort: GLI1 was expressed in 1 of 27 DDLPS, 1 of 9 leiomyosarcomas, and 2 of 10 pleomorphic liposarcomas, and it was negative in 23 well-differentiated liposarcomas and 9 unclassified pleomorphic sarcomas. Overall, GLI1 IHC was 91.3% sensitive and 98.0% specific for mesenchymal tumor types with driver GLI1 alterations among morphologic mimics. GLI1 expression was less frequent in other tumor types with GLI1 copy number gain. Given its specificity, in the appropriate morphologic context, GLI1 IHC may be a useful diagnostic adjunct for mesenchymal neoplasms with GLI1 alterations.

Pseudoendocrine Sarcoma: Clinicopathologic Analysis of 23 Cases of a Distinctive Soft Tissue Neoplasm With Metastatic Potential, Recurrent CTNNB1 Mutations, and a Predilection for Truncal Locations.

The number of recognized epithelioid soft tissue neoplasms continues to increase and includes epithelioid schwannoma, sclerosing epithelioid fibrosarcoma, and emerging entities such as sarcomas with GLI1 alterations. Here, we describe 23 cases of a previously unrecognized entity, provisionally termed "pseudoendocrine sarcoma." Pseudoendocrine sarcoma is a rare, distinctive tumor of uncertain lineage with a predilection for paravertebral soft tissue in older adults. Fifteen patients (65%) were male and 8 were female. Age at presentation ranged from 29 to 78 years (median: 62 y). Nineteen tumors (83%) occurred in truncal locations, including 15 tumors (65%) in paravertebral soft tissue; other locations included the posterior head (2 tumors), thigh (1), and orbit (1). Tumor size ranged from 2 to 19 cm (median: 6.35 cm). Pseudoendocrine sarcoma is composed of sheets, trabeculae, and nests of epithelioid or ovoid cells with indistinct borders, palely eosinophilic cytoplasm, and highly monomorphic, round nuclei with speckled chromatin. Pseudoglandular architecture was at least focally present in 16 tumors (70%), large extracellular hyaline globules were identified in 12 tumors (52%), and psammomatous calcifications were present in 8 (35%). Metaplastic ossification was identified in 2 tumors, and myxoid stroma was present in 1. Lymphovascular invasion was present in 5 of 18 tumors (28%). Immunohistochemistry demonstrated that most tumors showed nuclear positivity for ß-catenin (20/21 tumors; 95%), and some showed at least focal positivity for S-100 (9/22; 41%), desmin (3/8; 38%), or CD34 (2/8; 25%). All tumors were negative for neuroendocrine and epithelial markers, including synaptophysin (21 tumors), chromogranin (19), INSM1 (4), pan-K (16), CAM5.2 (13), AE1/AE3 (6), epithelial membrane antigen (20), and E-cadherin (13). DNA sequencing detected CTNNB1 point mutations in all 6 sequenced tumors: D32H, S33C, S33F, S37A, S37C, and S37F. RNA sequencing was negative for gene fusions in all 6 sequenced tumors. Clinical follow-up was available for 17 patients (74%; range: 4 mo to 20 y; median: 3.5 y), including 14 patients with >1 year of follow-up. Six of 14 patients with long-term follow-up experienced local recurrence (43%, at intervals of 3 to 6 y). One tumor showed a local lymph node metastasis within the primary excision specimen, and 3 patients developed distant lung metastases (21%). No patient died of the disease as yet. Despite its bland morphology and resemblance to the well-differentiated neuroendocrine tumor, pseudoendocrine sarcoma is best considered an intermediate-grade sarcoma, given its pathologic characteristics and clinical behavior.

RAF1-rearranged spindle cell tumour: report of two additional cases with identification of a novel FMR1-RAF1 fusion.

A subset of spindle cell tumours have been recently identified to harbor recurrent fusion genes, involving NTRK1/2/3, BRAF, RAF1, and RET. The precise classification of these fusion-positive tumours relies essentially on genomic profiling. Herein, we present our experience with two cases of spindle cell tumour which showed RAF1 rearrangement. Both tumours occurred in children with one in the left cheek (case 1) and the other one in the left buttock (case 2). Histologically, case 1 was a low-grade neoplasm characterized by uniform ovoid to short spindle cells showing "patternless" architecture with stromal hyalinization. Case 2 had an overtly malignant phenotype composed of long intersecting fascicles with increased cellularity and mitotic activity. By immunohistochemistry, tumour cells in case 1 showed co-expression of CD34 and S100 protein whereas in case 2 there was only focal staining of CD34 with no expression of S100 protein. Fluorescence in situ hybridization tests using NTRK1/2/3 (case 1 and case 2), ETV6, SS18, BRAF, ROS1, and ALK (case 2) break-apart probes were performed but yielded negative results. Subsequent next-generation sequencing (NGS) demonstrated PDZRN3-RAF1 fusion in case 1 and FMR1-RAF1 fusion in case 2, respectively, which were confirmed by FISH using RAF1 break-apart probe. This study further emphasizes the importance of molecular diagnostics in fusion-positive spindle cell tumours. In addition, we expand the genetic spectrum of RAF1-rearranged spindle cell tumour by describing a novel FMR1-RAF1 fusion gene.

GATA3 is a useful immunohistochemical marker for distinguishing sarcomatoid malignant mesothelioma from lung sarcomatoid carcinoma and organizing pleuritis.

Sarcomatoid malignant mesothelioma (SMM) tends to occur in the pleura and is morphologically similar to lung sarcomatoid carcinoma (LSC) and organizing pleuritis (OP). Because SMM often does not express mesothelial markers, it is very difficult to distinguish from LSC and OP. GATA-binding protein 3 (GATA3) is a specific immunohistochemical (IHC) marker of breast and urothelial carcinoma. We routinely find that GATA is expressed in MM; however, GATA3 expression in SMM and its reference value for distinguishing SMM from LSC and OP remain unclear. Here, we used IHC methods to detect the expression of GATA3 and classic mesothelial markers in 17 SMM, 12 LSC, and 7 OP cases. We detected the following expression rates in SMM versus LSC cases: GATA3 (70.6% vs. 16.7%, p = 0.008), calretinin (52.9% vs. 8.3%, p = 0.019), Wilms tumor (WT)-1 (64.7% vs. 0%, p = 0.000), D2-40 (47.1% vs. 16.7%, p = 0.126), CK5/6 (35.3% vs. 25.0%, p = 0.694), and pan-cytokeratin (CKpan) (88.2% vs. 100.0%, p = 0.498). The specificities of calretinin, WT-1, and GATA3 in distinguishing SMM from LSC were 91.7%, 100%, and 83.3%, respectively, and combinations of any two of these three markers exhibited 100% specificity for SMM. Notably, the sensitivity of calretinin+/WT1+ staining for SMM was only 23.5%, which increased to 64.7% after including GATA3. Furthermore, all OP cases showed partial or diffuse expression of CKpan, WT-1, and D2-40 but no GATA3 and calretinin expression. In conclusion, GATA3 is an IHC marker with excellent sensitivity and specificity for SMM, and the combined consideration of GATA3, calretinin, and WT-1 was best for distinguishing SMM from LSC. Moreover, CKpan, WT-1, and D2-40 had no value for distinguishing SMM from OP, and GATA3 and calretinin were the most specific markers for distinguishing these two lesions.

[Primary pulmonary myxoid sarcoma associated with translocation EWSR1-CREB1 and locorregional micrometastases]. / Sarcoma pulmonar mixoide primario asociado a traslocación EWSR1-CREB1 con micrometástasis locorregional.

Primary myxoid pulmonary sarcoma is a rare entity with an endobronchial growth. Although it should be included in the differential diagnosis of other sarcomas, its prognosis is usually favorable. We present the case of a 51-year-old patient with a mesenchymal tumor in the right lung, diagnosed as a primary pulmonary myxoid sarcoma, positive for EMA, vimentine and with a Ki-67 less than 5%; FISH revealed a EWSR1-CREB1 translocation.

[Sarcomatoid carcinoma of the nasal cavity: a case report and review of the literature]. / Carcinoma sarcomatoide de fosa nasal: a propósito de un caso y revisión de la literatura.

Spindle cell carcinoma of the nasal cavity is a rare variant of squamous cell carcinoma. We report a case of a 50 year-old male presenting with a polypoid mass in the left nasal cavity. Histologically, the tumor was biphasic, composed of non-keratinizing squamous nests and a sarcomatoid stroma with positivity for CKAE1-AE3. Metastatic ipsilateral lymph nodes were present and the patient underwent radical neck dissection, followed by adjuvant radiotherapy and cisplatin. Two years after diagnosis the patient is free of disease.

EWSR1-PATZ1-rearranged sarcoma: a report of nine cases of spindle and round cell neoplasms with predilection for thoracoabdominal soft tissues and frequent expression of neural and skeletal muscle markers.

The knowledge of clinical features and, particularly, histopathological spectrum of EWSR1-PATZ1-rearranged spindle and round cell sarcomas (EPS) remains limited. For this reason, we report the largest clinicopathological study of EPS to date. Nine cases were collected, consisting of four males and five females ranging in age from 10 to 81 years (average: 49 years). Five tumors occurred in abdominal wall soft tissues, three in the thorax, and one in the back of the neck. Tumor sizes ranged from 2.5 to 18 cm (average 6.6 cm). Five patients had follow-up with an average of 38 months (range: 18-60 months). Two patients had no recurrence or metastasis 19 months after diagnosis. Four patients developed multifocal pleural or pulmonary metastasis and were treated variably by surgery, radiotherapy, and chemotherapy. The latter seemed to have little to no clinical benefit. One of the four patients was free of disease 60 months after diagnosis, two patients were alive with disease at 18 and 60 months, respectively. Morphologically, low, intermediate, and high-grade sarcomas composed of a variable mixture of spindled, ovoid, epithelioid, and round cells were seen. The architectural and stromal features also varied, resulting in a broad morphologic spectrum. Immunohistochemically, the following markers were most consistently expressed: S100-protein (7/9 cases), GFAP (7/8), MyoD1 (8/9), Pax-7 (4/5), desmin (7/9), and AE1/3 (4/9). By next-generation sequencing, all cases revealed EWSR1-PATZ1 gene fusion. In addition, 3/6 cases tested harbored CDKN2A deletion, while CDKN2B deletion and TP53 mutation were detected in one case each. Our findings confirm that EPS is a clinicopathologic entity, albeit with a broad morphologic spectrum. The uneventful outcome in some of our cases indicates that a subset of EPS might follow a more indolent clinical course than previously appreciated. Additional studies are needed to validate whether any morphological and/or molecular attributes have a prognostic impact.

Crizotinib-associated Renal Cyst Formation in a Pediatric Patient With ALK+ Epithelioid Inflammatory Myofibroblastic Sarcoma.

BACKGROUND: Crizotinib is a first-generation tyrosine kinase inhibitor used for anaplastic lymphoma kinase (ALK) positive cancers. Simple and complex renal cyst formation is a rare complication of crizotinib use that has been reported previously in the adult population. CASE: We report a case of a right renal mass in a 17-year-old with ALK-positive epithelioid inflammatory myofibroblastic sarcoma treated with Crizotinib. After cessation of Crizotinib and initiating Alectenib, a second generation ALK inhibitor, the mass decreased in size and the patient remained asymptomatic without evidence of recurrence at three months of follow-up.

p-120 Catenin is a Useful Diagnostic Biomarker for Distinguishing Plasmacytoid and Sarcomatoid Variants From Conventional Urothelial Carcinoma.

CONTEXT.­: Plasmacytoid urothelial carcinoma (PC-UC) is an aggressive variant of urothelial carcinoma (UC), characterized by loss of E-cadherin (E-Cad)-mediated intercellular adhesion. Loss of E-Cad by immunohistochemistry can help diagnose PC-UC; however, sensitivity is limited. Expression of other cadherin-catenin adhesion complex members, that is, p-120 catenin (p-120) and ß-catenin (B-Cat), which are diagnostically useful for lobular breast carcinoma, remains unknown in UC. OBJECTIVE.­: To determine the utility of p-120 and B-Cat in conventional and variant UC. DESIGN.­: E-cadherin, B-Cat, and p-120 immunohistochemistry was performed in 25 conventional UCs and 33 variant UCs, including 22 PC-UCs, 6 sarcomatoid UCs (SUCs), and 5 micropapillary UCs. Membranous staining for all biomarkers was considered normal; however, any cytoplasmic staining or an absence of staining was considered diagnostically abnormal. Next-generation sequencing was performed on 8 PC-UC cases. RESULTS.­: E-cadherin, B-Cat, and p-120 showed membranous staining in all conventional and micropapillary UCs. In contrast, most PC-UCs were negative for E-Cad (17 of 22; 77%) with an additional 2 of 22 cases (9%) showing cytoplasmic with partial membranous staining. p-120 catenin demonstrated cytoplasmic or negative staining in 21 of 22 cases (95%). Most SUCs showed an absence of E-Cad (5 of 6; 83%) and cytoplasmic or negative p-120 in 5 of 6 cases (83%). Staining for B-Cat was also abnormal in a subset of PC-UCs and SUCs. Five PC-UC cases that harbored CDH1 gene variants were p-120 cytoplasmic positive. CONCLUSIONS.­: p-120 catenin is a useful adjunct biomarker to E-Cad in the clinically important distinction of PC-UC and SUC from conventional UC. In particular, the combination of cytoplasmic p-120 and loss of E-Cad is strongly supportive of PC-UC and SUC.

Sarcomatoid Mesothelioma: A CDKN2A molecular analysis of 53 cases with immunohistochemical correlation with BAP1.

Fifty-three cases of sarcomatoid pleural mesothelioma were evaluated for CDKN2A (p16) homozygous deletion and correlated with BRCA-associated protein-1 (BAP1) expression by immunohistochemistry. The patients are 45 men and 8 women between the ages of 37 and 79 years (average age: 58 years), who presented with symptoms of chest pain, cough, and weight loss. Diagnostic imaging showed the presence of diffuse pleural thickening with encasement of the lung parenchyma in all the cases. All patients were surgically treated with extrapleural pneumonectomy. Loss of BAP1 reactivity was seen in 49 tumors and p16 homozygous deletion was seen in 41 tumors, while in 16 patients either BAP1 or p16 were noncontributory to the diagnosis of mesothelioma. However, we were able to detect a better survival rate in those patients in whom BAP1 was lost and p16 showed homozygous deletion. Our findings showed that even though the use of BAP1 and p16 are important tools in the diagnosis of mesothelioma, a proportion of cases still remains negative with approximately 30 % of the cases in which the concordance of BAP1 loss and p16 homozygous deletion will not be present. We consider that the final diagnosis of mesothelioma is best accomplished by a global interpretation of clinical, radiographic, and pathological features including immunohistochemistry and molecular studies.

Non-small cell lung carcinomas with a minor sarcomatoid component and pleomorphic carcinomas are associated with high expression of programmed death ligand 1.

Pleomorphic carcinomas are known to be highly programmed death ligand 1 (PD-L1) positive non-small cell lung cancer (NSCLC) types. However, the level of PD-L1 expression in lung carcinomas with a minor sarcomatoid component, comprising less than 10 % of the tumor mass, has not been determined yet. We hypothesized that NSCLC with a minor sarcomatoid component is more closely related to pleomorphic carcinomas in terms of PD-L1 expression than to NSCLC types without sarcomatoid features. The surgical resections from 690 lung carcinoma patients were retrospectively analyzed for the presence of PD-L1 by means of immunohistochemistry using the 22C3 PharmDx assay. The tumor proportion score system was applied to quantify the level of PD-L1 expression. Membranous staining present in ≥ 1 % of tumor cells was chosen as the cut-off to define a positive result for PD-L1 expression. Tumors were allocated into one of four subgroups: "adenocarcinoma", "squamous cell carcinoma", "pleomorphic carcinoma", or "NSCLC with a minor sarcomatoid component". PD-L1 expression in pleomorphic carcinomas (26/32, 81.3 %) and in the subgroup of NSCLC with a minor sarcomatoid component (35/46, 76.1 %) was identified in a comparable proportion of cases. Pleomorphic carcinomas were significantly more often PD-L1 positive than adenocarcinomas (p < 0.001) or squamous cell carcinomas (p = 0.0015). Accordingly, the proportion of PD-L1 expressing NSCLC with a minor sarcomatoid component was significantly higher than that of the adenocarcinoma (p < 0.001) or squamous cell carcinoma (p = 0.002) subgroup. In summary, we identified a presumable new subgroup of highly PD-L1 positive neoplasms within the NSCLC spectrum that is related to pleomorphic carcinomas in terms of PD-L1 expression. Further investigation regarding genetic relation and mechanism of PD-L1 expression in these two NSCLC categories is recommended.

[Clinical challenges and implications of intratumor heterogeneity]. / Retos e implicaciones clínicas de la heterogeneidad intratumoral.

Tumors display a high, albeit variable, grade of intratumor heterogeneity, both from a clinical and a morphological viewpoint. Furthermore, recent methods of large-scale molecular analysis demonstrate to what extent tumors can also be heterogeneous from a molecular perspective. This is of paramount importance for patients as it has a great impact on the success of so-called precision therapies and explains the reason for a significant number of therapeutic failures in modern oncology. We present an up-to-date review of the latest findings in a group of tumors with a high social impact, commonly seen in the daily routine of the pathology laboratory.

[Cardiac intimal sarcoma: A case report of a rare tumor with peculiar histopathological findings]. / Le sarcome intimal cardiaque : tumeur rare illustrée par un cas de présentation histopathologique inhabituelle.

Primary cardiac sarcomas are rare tumors with poor prognosis. Intimal sarcoma, a mesenchymal malignant tumor described mainly in the great vessels, may rarely involve the heart. Herein we describe the case of a 70-years-old female who was found to have a left atrial mass during an investigation of a new onset dyspnea. The patient underwent surgery and the resected mass was found to be an intimal sarcoma. The objectives of this report were to describe a case of this rare disease entity and to discuss its pathological and molecular findings based on relevant literature.

An autopsy case of pulmonary artery intimal sarcoma: detailed observation of tumor and its related lesions in pulmonary arteries.

We report an autopsy-proven case of a 33-year-old man who died of intimal sarcoma of the pulmonary artery. A large mass (5×4 cm) occluded the main and bilateral pulmonary arteries. Tumor cell morphology was consistent with that of undifferentiated pleomorphic sarcoma. Comprehensive histological observation of 18 pulmonary arteries from proximal to distal revealed continuous extension of the tumor from the main to the subsegmental arteries along the intima, forming an arteriosclerosis-like intimal thickening. Distal small arteries were also affected by eccentric intimal thickening or recanalization. Lung parenchyma was not involved, although there were two wedge-shaped small pulmonary infarctions caused by tumorous obstruction of the associated arteries. Histological results indicated that the intimal sarcoma in the pulmonary artery, which appeared occlusive with growth limited to the proximal artery, had in fact already spread more peripherally than expected. Both the proximal lesions and the distal small arteries were affected by peripheral tumor emboli or by pulmonary hypertension induced by the proximal tumor. However, as seen in this case, most of the occlusive tumor was located locally and intraluminally, in the proximal artery, and removing the proximal tumor by pulmonary endarterectomy was considered effective for symptomatic improvement.

Sarcomatoid Variant of Primary Cutaneous Anaplastic Large Cell Lymphoma.

Sarcomatoid variant of primary cutaneous anaplastic large cell lymphoma is rare and is a diagnostic challenge. Clinical manifestation often mimics that of an infectious disease. Predominance of spindle cells in the biopsy specimen prevents from suspecting lymphoma. Here, we report the fourth case of this entity with good prognosis. A 30-year-old woman presented with several nodules on the whole body. The biopsy revealed infiltration of spindle cells in the dermis with myxomatous background. The spindle cells were positive for CD4 and CD30 and negative for CD3, CD8, CD20, and anaplastic lymphoma kinase. Although most of the skin lesions spontaneously resolved, a new red nodule progressively expanded on the left axilla. Finally, the patient received chemotherapy, which resulted in complete remission. The patient is free of disease for 18 months.

Sarcomatoid carcinomas of the gallbladder: clinicopathologic characteristics.

Sarcomatoid carcinomas recently came into the spotlight through genetic profiling studies and also as a distinct model of epithelial-mesenchymal transition. The literature on sarcomatoid carcinomas of gallbladder is limited. In this study, 656 gallbladder carcinomas (GBC) were reviewed. Eleven (1.7%) with a sarcomatoid component were identified and analyzed in comparison with ordinary GBC (O-GBC). Patients included 9 females and 2 males (F/M = 4.5 vs. 3.9) with a mean age-at-diagnosis of 71 (vs. 64). The median tumor size was 4.6 cm (vs. 2.5; P = 0.01). Nine patients (84%) presented with advanced stage (pT3/4) tumor (vs. 48%). An adenocarcinoma component constituting 1-75% of the tumor was present in nine, and eight had surface dysplasia/CIS; either in situ or invasive carcinoma was present in all cases. An intracholecystic papillary-tubular neoplasm was identified in one. Seven showed pleomorphic-sarcomatoid pattern, and four showed subtle/bland elongated spindle cells. Three had an angiosarcomatoid pattern. Two had heterologous elements. One showed few osteoclast-like giant cells, only adjacent to osteoid. Immunohistochemically, vimentin, was positive in six of six; P53 expression was > 60% in six of six, keratins in six of seven, and p63 in two of six. Actin, desmin, and S100 were negative. The median Ki67 index was 40%. In the follow-up, one died peri-operatively, eight died of disease within 3 to 8 months (vs. 26 months median survival for O-GBC), and two were alive at 9 and 15 months. The behavior overall was worse than ordinary adenocarcinomas in general but was not different when grade and stage were matched. In summary, sarcomatoid component is identified in < 2% of GBC. Unlike sarcomatoid carcinomas in the remainder of pancreatobiliary tract, these are seldom of the "osteoclastic" type and patients present with large/advanced stage tumors. Limited data suggests that these tumors are aggressive with rapid mortality unlike pancreatic osteoclastic ones which often have indolent behavior.