Degree Of Morphological Overlap Research Articles

Endometrioid Squamous Proliferations of the Endometrium Express Alpha-Methylacyl-CoA Racemase (P504s).

Squamous morular metaplasia is closely associated with endometrioid proliferative lesions such as endometrial intraepithelial neoplasia, whereas endometrioid adenocarcinoma may also demonstrate squamous differentiation (morular or nonmorular). Alpha-methylacyl-CoA racemase (AMACR; P504s) is an immunohistochemistry marker expressed in many tumors, including prostate adenocarcinoma, renal cell carcinoma, and in a subset of gynecologic carcinomas, predominantly of clear cell histology. In small biopsy samples, the distinction between cervical high-grade squamous intraepithelial lesions (HSILs) involving endocervical glands from endometrioid squamous proliferations can be challenging, given their anatomic vicinity and some degree of morphologic overlap. Following the observation of AMACR positivity by immunohistochemistry within squamous morules in an index case, 35 endometrial samples containing squamous morular metaplasia (25) and nonmorular squamous metaplasia (10), and 32 cases of cervical HSIL involving endocervical glands were stained with AMACR. The endometrial cohort consisted of 2 benign anovulatory endometrium, 7 endometrial polyps, 7 endometrial intraepithelial neoplasia, 4 atypical polypoid adenomyomas, and 15 endometrioid adenocarcinomas. Positive cases were scored as diffuse (≥50%) or focal (<50%). AMACR staining was present in 96.7% of endometrial squamous lesions, including 14 (93.3%) of endometrioid carcinomas, and in all cases of endometrial intraepithelial neoplasia, endometrial polyps, atypical polypoid adenomyomas, and anovulatory endometrium with squamous morular metaplasia or nonmorular squamous metaplasia. In comparison, only 2 cases (5.8%) of cervical HSIL demonstrated positivity for AMACR. In conclusion, AMACR can reliably differentiate the cervical versus endometrial origin of squamous lesions in small biopsy specimens.

Detecting disease-defining gene fusions in unclassified round cell sarcomas using anchored multiplex PCR/targeted RNA next-generation sequencing-Molecular and clinicopathological characterization of 16 cases.

Detection of disease-defining gene fusions in sarcoma has led to refining their classification, as well as to discover several new entities. The advent of anchored multiplex PCR/targeted RNA next-generation sequencing (AMP/RNA-seq) has allowed for the development of scalable platforms that can simultaneously examine multiple fusion transcripts without prior knowledge of specific fusion partners.In this study, we assess the utility of a FusionPlex sarcoma panel analysis by AMP/RNA-seq to detect disease-defining gene fusions in 16 cases of undifferentiated round cell sarcoma in which prior diagnostic work-up could not establish a definitive diagnosis. The clinical and pathologic features of these cases were correlated with the molecular findings. Validation of the method using 41 cases with known diagnoses showed analytic sensitivity and specificity of 98% and 100%, respectively. Of the 16 cases of undifferentiated round cell sarcoma, gene fusions were found in 9 (56%). These included three cases with CIC-DUX4 fusion, two cases with BCOR-CCNB3, and four single cases with CIC-NUTM2A, HEY1-NCOA2, EWSR1-NFATC2, and NUT-MGA1 fusions. Overall, despite some degree of morphologic overlap, all fusion-positive cases had distinct morphologic features, which can be helpful for their histologic classification. We also describe the first adult case of MGA-NUTM1 fusion sarcoma, as well as cartilaginous differentiation in a BCOR-CCNB3 fusion sarcoma, which has not been previously reported. Our study demonstrated that FusionPlex sarcoma panel analysis, in the appropriate morphologic context, is a sensitive and precise ancillary method for the detection of disease-defining gene fusions in undifferentiated round cell sarcomas, aiding in their definitive classification.

Identification of conifer stomata in pollen samples from western North America

Conifer stomata provide important paleoecological information for determining the composition of past plant communities, particularly at the local scale and when plant macrofossils are absent. To aid efforts to identify conifer stomata in fossil pollen samples from western North America, we describe the stomatal morphology of 19 conifer species that occur in the region, with emphasis on species that are present in the conifer-dominated forests along the northwest Pacific coast. We measured 10 morphological traits in a total of 315 stomata from these species. Morphological variability within species and the degree of morphological overlap among species precludes reliable identification to the species level; however, stomatal morphology is relatively consistent within genera and sufficiently unique to permit identification to genus. We used classification and regression trees to identify the critical morphological features for stomata identification and to build classification models. We then used these classification models as the basis for dichotomous identification keys for complete and incomplete conifer stomata. Identification of conifer stomata in fossil pollen samples from western North America should enhance paleoecological records from the region by providing evidence of local conifer presence and potentially clarifying their arrival times. Conifer stomata also provide a possible avenue for increasing taxonomic resolution in some paleoecological records: Pseudotsuga and Larix as well as members of the Cupressaceae family have indistinguishable pollen morphologies, but our results show that their stomata can be differentiated in most instances.

Mammary-type Myofibroblastoma: Clinicopathologic Characterization in a Series of 143 Cases.

Mammary-type myofibroblastoma (MTMF) is a benign mesenchymal neoplasm initially described to occur in the breast. MTMF is typically CD34 and desmin positive and genetically has rearrangement or deletion of 13q14, resulting in loss of Rb expression by immunohistochemistry (IHC). Although the wider anatomic distribution of MTMF is increasingly recognized, no large series with clinicopathologic information has been reported to date. Archival cases were retrieved, and the diagnosis of MTMF was confirmed. Hematoxylin and eosin-stained slides and IHC slides were reviewed when available (CD34, Desmin, Rb, SMA, S100, EMA, MDM2, CDK4). The patient age, sex, tumor anatomic location and size, preceding symptoms, and margin status were recorded when possible. Clinical follow-up data were requested for tumor recurrence, metastasis, and patient status at last follow-up. A total of 143 cases of MTMF comprised this study, affecting 94 (66%) male and 49 (34%) female individuals. Mean tumor size was 6.6 cm (range, 1 to 22 cm). Anatomic locations included: inguinal/groin region (65; 45%), breast (15; 10%), chest wall/axilla (7; 5%), trunk (17; 12%), lower (18; 13%) and upper (2; 1%) extremities, or intra-abdominal/retroperitoneal (14; 10%). MTMFs were characterized by spindle cells with relatively short, stubby nuclei and a variable adipocytic component. Hyalinization and myxoid stroma were common. Less common morphologic features included nuclear atypia, epithelioid tumor cell morphology, and neurilemmoma-type nuclear palisading. CD34 and desmin were positive in 89% and 91%, respectively, and were both negative in 3%. Rb expression was lost in 92% (57/62). No cases with follow-up data available had tumor recurrence, although 1 case was reportedly a recurrence itself. In summary, MTMF appears more common at extramammary sites than in the breast and can cause diagnostic difficulty when atypia or epithelioid morphology is present or when located in an unusual anatomic location. MTMF is frequently positive for CD34 and desmin by IHC; however, rare cases are negative for both. There is no evidence of any significant recurrence risk for MTMF, even in the presence of positive resection margins. The degree of morphologic overlap between spindle cell lipoma, cellular angiofibroma, and MTMF, in combination with shared genetics and slightly overlapping anatomic distribution, raises the question of whether or not these tumors are truly distinct entities or instead represent points along a single spectrum of genetically related tumors.

Fine needle aspiration cytology features of poorly differentiated thyroid carcinoma

Poorly differentiated thyroid carcinoma (PDTC) is an uncommon thyroid malignancy with biological behaviour intermediate between well-differentiated and undifferentiated thyroid carcinoma. The cytological diagnosis of PDTC is often difficult as a result of a lack of well-established cytomorphological features and a considerable degree of morphological overlap with other commoner thyroid neoplasms. To review the cytomorphological features of PDTC with the aim of highlighting salient diagnostic morphological features and differential diagnostic problems. Seven cases of histologically proven PDTC with available aspiration cytology smears were reviewed for the presence of distinguishing cytomorphological features. The architectural arrangement of tumour cells was the most important diagnostic parameter. Cellular nests, three-dimensional clusters dyscohesive aggregates and singly dispersed cells in the background were present in all cases. A unique 'garlanded appearance', owing to the peripheral orientation of nuclei within the tumour cell clusters, was noted (71.4%) along with the presence of basement membrane-like material (71.4%). Transgressing vessels (85.7%) and endothelial wrapping of cell clusters (71.4%) were also noted. Interestingly, most cases lacked necrosis and mitotic activity that are included in the histological diagnostic criteria for PDTC. Although PDTC has considerable cytomorphological overlap with well-differentiated thyroid tumours, this present study highlights certain cytomorphological features that may suggest the correct pre-operative diagnosis, important for the appropriate management.

Untangling the complex: molecular patterns in Trachylepis variegata and T. punctulata (Reptilia: Scincidae)

The Mabuya [=Trachylepis] lacertiformis complex is comprised of four species with a high degree of morphological overlap and a convoluted taxonomic history. Of these four species, T. punctulata and T. variegata possess the broadest ranges, together covering much of southern Africa. These two forms were elevated to species status based on slight differences in morphology, ecological differentiation and seemingly allopatric distributions. The molecular relationships of these two species, referred to as the T. variegata complex, have not been investigated. Here, we use both mitochondrial (ND2) and nuclear (RAG-1) data to test whether T. variegata and T. punctulata form reciprocally monophyletic assemblages, supporting species recognition. While we do not find direct evidence that these two species have a sister taxon relationship, our results are likely driven by an undescribed lineage within T. punctulata or by a sampling artefact. Based on all available evidence, we conservatively support recognition of T. variegata and T. punctulata as distinct species, but recommend further investigation of relationships within T. punctulata to resolve whether additional lineages are present in this group.

Rhabdomyosarcoma of the Urinary Bladder in Adults: Predilection for Alveolar Morphology With Anaplasia and Significant Morphologic Overlap With Small Cell Carcinoma

Rhabdomyosarcoma (RMS) represents the most common malignant soft tissue tumor in children and adolescents with the urinary bladder representing a frequent site. Most of these urinary bladder tumors are embryonal RMS, predominantly the botryoid subtype. RMSs of the urinary bladder in adults are distinctively rare and the subject of only case reports. We report the clinicopathologic features of 5 bladder neoplasms with rhabdomyosarcomatous differentiation in adults and emphasize the differential diagnosis in the adult setting. The patients, 4 men and 1 woman, ranged in age from 23 to 85 years (mean 65.4 y). Gross hematuria was the most common initial symptom, although 2 patients had metastatic disease at presentation. Four cases were pure primary RMSs of the bladder and 1 case was a sarcomatoid urothelial carcinoma with RMS representing the extensive heterologous component. All 5 cases demonstrated a diffuse growth pattern (ie, non-nested), of which 4 cases had nuclear anaplasia (Wilms criteria without the atypical mitotic figure requirement); only 1 case (the sarcomatoid carcinoma) showed obvious rhabdomyoblastic differentiation (ie, strap cells). Three cases were of the alveolar subtype (1 admixed with embryonal histology) and 2 were RMS, not further classified. Microscopically, all tumors had a primitive undifferentiated morphology with cells containing scant cytoplasm, varying round to fusiform nuclei with even chromatin distribution, and frequent mitoses. The degree of morphologic overlap with small cell carcinoma of the bladder, a relatively more common round cell tumor in adults, was striking. The epithelial component of the sarcomatoid carcinoma was high-grade invasive urothelial carcinoma with glandular differentiation. No other case had previous history of bladder cancer or concurrent carcinoma in situ or invasive urothelial carcinoma. All tumors showed immunohistochemical expression for desmin, myogenin, and/or MyoD1. Synaptophysin was performed in 4 cases, and 3 showed weak cytoplasmic immunoreactivity. Two patients received chemotherapy, 2 underwent cystectomy, and 1 had transurethral resection alone. Outcome data were available in 4 cases, and all 4 died of disease (1, 4, 8, and 8 mo). In conclusion, (1) RMS of the urinary bladder in adults more commonly presents as a primitive round blue cell neoplasm that has significant morphologic and immunohistochemical overlap with small cell carcinoma of the bladder. (2) Although RMS in children generally have a botryoid embryonal histology with favorable outcome, bladder RMS in adults frequently demonstrates alveolar or unclassified histology, commonly with anaplasia, and have a uniformly aggressive clinical course.

An Approach to the Classification of Spindle Cell Proliferations in the Urinary Bladder

Spindle cell proliferations of the urinary bladder are uncommon but may cause significant diagnostic difficulty resulting from the degree of morphologic overlap between clinically benign and malignant lesions. These difficulties may be amplified in small biopsies because some of the more specific diagnostic features may not be present for evaluation. In addition, the number of different diagnostic terms applied to the same entity has added confusion to this diagnostic area. This review discusses the nomenclature, morphologic criteria, and immunohistochemical features used to classify spindle cell proliferations occurring in the urinary bladder, including those with myofibroblastic, smooth muscle, skeletal muscle, epithelial (sarcomatoid urothelial carcinoma), fibroblastic, and neural differentiation. A separate discussion of 5 challenging differential diagnostic scenarios is also presented.

Morphological Diversification and Taxonomy Among the Varieties of &lt;I&gt;Pedicularis bracteosa&lt;/I&gt; Benth. (Orobanchaceae)

Multivariate and univariate analyses were used to investigate patterns of floral and foliar morphological diversification among the eight taxonomic varieties of Pedicularis bracteosa (Orobanchaceae). Canonical discriminant analysis supported six varieties but not without considerable morphological overlap. Discrimination was most strongly based upon three floral characters: galea shape, throat length, and calyx tip length; and secondarily on three foliar characters: subtending bract width, longest leaflet width, and longest leaflet length. Analysis of variance on the ratio between calyx length and the length of the connate portion of the calyx did not corroborate a taxonomic difference among all varieties. Because galea shape is associated with specific pollination syndromes that promote reproductive isolation in other Pedicularis species, selection by the different pollinating behaviors of queens versus worker castes of the same species of bumblebees may be driving the diversification of floral morphology. While the taxa are largely allopatric and supported by several strong morphological discriminators, the high degree of morphological overlap among them does not justify their re-ranking above variety. Lack of discrimination between varieties siifolia and canbyi argues for their merger into a single taxon. A revised key to the varieties reflecting the results of this study is presented.

Two new tertiary scalpellid barnacles (Cirripedia: Thoracica) from the Chatham Islands, New Zealand

Abstract Two new calanticine scalpellids, Smilium chathecum and Calantica (?Scillaelepas) pittensis are described from the Chatham Islands. They are significant in that they represent relatively early forms of their respective genera, and demonstrate some degree of morphological overlap between extant and ancestral taxa. The paleoenvironment of S. chathecum is discussed, and a review of the status of Calantica (Scillaelepas) and the Calanticinae is included.