Rationale: Pulmonary artery intimal sarcoma is a rare tumor with exceptionally high mortality and easily misdiagnosed as pulmonary thromboembolism pulmonary thromboembolism (PTE) due to the nonspecific clinical presentation and symptom. Misdiagnosis or untimely diagnosis makes the disease progress to an advanced stage and eventually leads to a poor prognosis. Patient concerns: A 37-year-old Chinese female presented with chest tightness and dyspnea for 3 months. Echocardiography and chest computed tomography revealed an intraluminal obstruction of the pulmonary arteries. Tests of serum tumor makers showed slight elevation for carbohydrate antigen-125, and α-fetoprotein. PTE was suspected according to the radiological and laboratory findings. Diagnosis: Microscopic findings of the presumed thrombus showed prominent myxoid and edematous background with atypical spindled cells and curvilinear vascularity. Immunohistochemical staining demonstrated that the atypical spindled cells were positive for vimentin but negative for CK, S100, SMA, desmin, CD68, STAT6, CD34, β-catenin, ALK-p80, p53, and MDM2. According to the radiological and pathological findings, the diagnosis of fibrosarcoma of pulmonary artery was made. Interventions: The patient underwent surgical resection and the mass was excised as completely as possible. Outcome: Follow-up information showed no evidence of recurrence or metastasis after 3 months postresection. Lessons: Because of the low incidence rate, nonspecific clinical symptoms, and radiological findings, primary fibrosarcoma of the pulmonary artery is commonly misdiagnosed as PTE. Pathological examination is necessary to confirm the diagnosis.

Rationale:Primary central nervous system histiocytic sarcoma (PCNSHS) is a rare lymphohematopoietic tumor with a histiocytic cell origin. To our knowledge, only 28 cases have been published in English and 2 cases in Chinese.Patient concerns:A 49-year-old Asian female presented to the hospital with a 2 month history of hypomnesia, odynophagia, and gait disorder. Physical examination demonstrated decreased lower extremity muscle strength. The patient denied a history of malignancy.Diagnoses:Radiology demonstrated a lesion in parietal lobe with uniformenhancement. Histologic analysis showed pleomorphic tumor cells with a loose arrangement, effacing the normal brain tissue. The tumor cells exhibited abundant eosinophilic cytoplasm, highly atypical nuclei and predominant nucleoli. Immunohistochemistry revealed positive immunoreactivity for CD45, lysozyme, CD68, and CD163, and negative for pan-cytokeratin (CK), epithelial membrane antigen (EMA), glial fibrillary acidic protein (GFAP), CD3, CD20, CD1a, CD79a, CD138, oligodendrocyte transcription factor (olig2), CD15, melan-A, CD30, CD21, CD35, Human Melanoma Black-45 (HMB45), and anaplastic lymphoma kinase-1 (ALK-1). The diagnosis of PCNSHS was rendered.Interventions:The patient underwent complete surgical resection and adjuvant radiotherapy.Outcomes:Follow-up information shows the patient died 8 months following the initial diagnosis.Lessons:PCNSHS is extremely rare with an aggressive clinical course. Immunohistiochemistry is necessary to make this diagnosis and to exclude other primary intracranial and lymphohematopoietic tumors. Further research is required to improve the outcome of patients with PCNSHS.

Angiomyolipoma (AML) is a rare mesenchymal neoplasm of the tumor, composed of a varying heterogeneous mixture of three tissue components: blood vessels, smooth muscle and adipose cells. Hepatic AML may demonstrate a marked histological diversity. We herein present one case of hepatic AML exhibiting prominent inflammatory cells in the background, which happened in a 61-year-old Chinese female patient, without signs of tuberous sclerosis. Histologically, the striking feature was the infiltration of numerous inflammatory cells in the background, including small lymphocytes, plasma cells, and eosnophils. The tumor cells were spindled and histiocytoid in shape, with slightly eosinophilic cytoplasm, and arranged along the vessels or scattered among the inflammatory background. Sinusoid structure was obviously seen in the tumor. Mature adipocytes and thick-walled blood vessels were focally observed at the boundaries between the tumor and surrounding liver tissues. The tumor cells were positive immunostaining for HMB-45, Melan-A, and smooth muscle actin. The inflammatory AML should be distinguished from other tumors with inflammatory background such as inflammatory myofibroblastic tumor and follicular dendritic cell tumor and deserves wider recognition for its occurrence as a primary hepatic tumor.Virtual slidesThe virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1828633072762370

Langerhans' cell histiocytosis is a disease usually found in children and characterized by idiopathic proliferation of histiocytes in the reticuloendothelial system. Intracranial Langerhans' cell histiocytosis presenting as multifocal intraparenchymal lesions is very rare. In this article, the authors report on a 4-year-old boy diagnosed with multifocal intraparenchymal Langerhans' cell histiocytosis concomitant with an arachnoid cyst. After a series of laboratory examinations, the right frontal mass was surgically excised. Histological examinations confirmed the diagnosis of intracranial Langerhans' cell histiocytosis. The patient's intracranial hypertension symptoms were alleviated, and the remaining foci were treated by Langerhans' cell histiocytosis-directed standard chemotherapy. At the 8-month follow-up visit, no recurrence of the excised lesion was found, and no change in the size of other lesions was seen. Supratentorial intracerebral lesions with mass effect and enhancement have rarely been described; in this report, the histological features of and therapeutic options for such a case are discussed.

Papillary thyroid carcinoma (PTC) is the most common malignant neoplasm of the thyroid gland; fine needle aspiration cytology is the most basic and reliable diagnostic method before PTC operation. However, it is not clear which cell morphological changes can be used as a reliable standard for the diagnosis of PTC. A retrospective analysis was performed on 337 patients with PTC confirmed by postoperative histology. An additional 197 randomly selected patients with benign thyroid lesions were included in the study and used as a control group. True papillary arrangements, swirl arrangements, and escape arrangements had high specificity, all of which were 100%, but only swirl arrangements had ideal sensitivity (77.61%). The nuclear volume characteristics had a high sensitivity of more than 90%, but the specificities of both nuclear crowding and nuclear overlap were too low, only 16.34% and 23.35%. The sensitivities of five nuclear structural characteristics were more than 90%, but only the specificity of intranuclear cytoplasmic pseudoinclusions (INCIs) reached 100%, nuclear contour irregularity and pale nuclei with powdery chromatin also had ideal interpretation value except for grooves and marginally placed micronucleoli. Although the sensitivity of psammoma bodies (PBs) was low, the specificity was 100%. In terms of preparation methods, the method of liquid-based preparation (LBP) is obviously better than that of conventional smears. The diagnostic efficiency by the combined detection method of parallel tests showed that without reducing the specificity, the sensitivity increased with the increase of the number of morphological characteristics and finally reached 98.81%. The INCIs and swirl arrangements are the most common and important indicators for the diagnosis of PTC, whereas papillary-like arrangements, the crowding and overlap of nuclear, grooves, marginally placed micronucleoli, and multinucleated giant cells are of little significance for the diagnosis of PTC.

Objectives-This study aimed to investigate the reliability of 3-dimensional (3D) ultrasound in screening for developmental dysplasia of the hip (DDH) by comparing the results with those of 2-dimensional (2D) ultrasound.Methods-One hundred five infants who were younger than 6 months were enrolled in this study. All of the infants underwent 2D and 3D ultrasound scanning for DDH by novices and experts, and the images were graded by a lead expert. The scanning time and image grades were analyzed by Student t tests (P < .05). The consistency of the α angle measurement between the novices and experts was evaluated by the intraclass correlation coefficient (ICC).Results-The 105 infants included 34 boys and 71 girls. On 2D scanning, there was agreement between the experts about the correct diagnosis, whereas in the novice group, 41 infants had misdiagnoses. There were no misdiagnoses with 3D scanning in either group. In the novice group, the mean image grades AE SD were 4.2 AE 1.3 (2D ultrasound) and 8.1 AE 0.7 (3D ultrasound; P < .05). In the expert group, the mean image grades were 7.4 AE 1.0 (2D ultrasound) and 8.2 AE 1.0 (3D ultrasound; P < .05). There was no statistically significant difference between the groups in the grades for 3D ultrasound (P = .83). The scanning time for 3D ultrasound was shorter than that for 2D ultrasound in both groups (P < .05). In the novice group, the ICC of the α angle between the 2D and 3D ultrasound results was 0.34, and in the expert group, it was 0.92. The ICCs were 0.35 and 0.84, respectively when comparing 2D and 3D ultrasound results in the groups.Conclusions-Three-dimensional ultrasound required less time and showed greater inter-rater reliability than 2D ultrasound for detecting DDH.

Background Metaplastic thymoma (MT) is a very uncommon thymoma type, with biphasic differentiation as one of its histological characteristics. This histological pattern, however, can also be mistaken for type A thymoma and the A component in type AB thymoma. Methods Postoperative specimens were collected from five MT and four type A thymomas with a retrospective analysis involving immunohistochemistry, fluorescence in situ hybridization (FISH) and next-generation sequencing (NGS). Results The histological morphology of the MT overlapped with that of the type A thymoma. With immunostains, the former’s spindle cell components expressed vimentin and EMA, but not CD20. In MT, 3/5 cases had the nuclear expression of YAP1. The spindle cell component of the type A thymoma was found to express CD20. In all five cases of MT, FISH detection revealed YAP1–MAML2 fusion, which was not found in any type A thymoma cases. NGS sequencing confirmed YAP1–MAML2 rearrangement in all five cases of MT, and mutations in POLE and HRAS were also found in two cases, respectively. GTF2I c.74146970 T > A mutations were found in all cases of type A thymoma, and HRAS and NRAS mutations were found in two cases, but no YAP1–MAML2 rearrangement was evident. Conclusions For the diagnosis and differential diagnosis of challenging cases, the YAP1–MAML2 rearrangement and GTF2I mutation were both significant molecular events specific to MT and type A thymoma, respectively.

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