Primary follicular dendritic cell sarcoma of the pleura: A clinicopathological and immunohistochemical study of two cases.

Two cases of primary follicular dendritic cell sarcoma (FDCS) of the pleura are presented. The patients are a woman 76-years-old and a man 64-years-old who presented with nonspecific symptoms including chest pain, dyspnea, and cough. Clinical history did not disclose any pertinent history of previous malignancy. Diagnostic imaging showed the presence of a pleural-based mass in both patients and a thoracotomy with resection of the pleural mass was performed. Both tumors were described as solid, light tan, and with ill-defined borders. Histologically, both tumors showed similar histological features, namely the presence of a spindle cellular proliferation composed of elongated cells with fibrillary cytoplasm, oval nuclei, and conspicuous nucleoli. Mild to moderate cellular atypia was present, while mitotic figures ranged from 3 to 4 per 10 high power fields. Mature lymphocytes and plasma cells were also present dispersed throughout the tumor. Immunohistochemical stains in both cases show positive staining for CD21 and CD35 while focal staining was present for D2-40 and clusterin, while negative for other markers including keratin, desmin, S-100 protein, calretinin, and STAT-6. Clinical follow up shows that both patients have remained alive 12 and 14 months after initial diagnosis. The cases herein described represent an unusual occurrence of FDCS arising in the pleural surface and one that must be kept in mind when dealing with spindle cell tumors of the pleura.

Primary pulmonary hyalinizing spindle cell tumor with giant rosettes: A clinicopathological and immunohistochemical study of 2 cases.

Two cases of primary intrapulmonary hyalinizing spindle cell tumor with giant rosettes are presented. The patients are one woman and one man ages 37 and 42 years respectively. Both patients presented with non-specific symptoms of cough, dyspnea, and chest pain. Imaging revealed the presence of an intrapulmonary mass. One tumor was located in the left lower lobe while the other tumor was in the right upper lobe. Both patients underwent lobectomy. The tumors ranged from 2.4 to 3.0 cm in greatest dimension and were characterized by the presence of a bland spindle cell proliferation with areas of hyalinization and the presence of the so-called giant rosettes. Immunohistochemical stains were performed and the spindle cell component show positive staining for vimentin and negative staining for Bcl-2, CD34, STAT6, p40. Keratin immunohistochemical stain highlighted the entrapped alveolar epithelium while S-100 protein showed weak focal staining in the spindle cells. Both patients have remained alive and well without evidence of recurrence or metastasis for a period of 6 to 14 months post-surgical resection. The cases herein presented highlight the ubiquitous distribution of this tumor and underscores the importance of keeping this particular tumor in the differential diagnosis of spindle cell tumors of the lung.

Thymoma: An Overview.

Thymomas are considered one of the most prevalent types of mediastinal epithelial tumors, which frequently develop in the anterior mediastinum. Due to their rarity, these tumors' nomenclature, classification, and staging are likely to be the subject of debate and argument for most expert pathologists. Furthermore, the significance of thymoma histologic classifications have been debated over the past twenty years. While certain advocates argue that staging at the time of diagnosis is more significant, others believe that histologic subtyping has a significant impact on how patients behave clinically. In this review, we will focus on some of the challenges that diagnostic surgical pathologists may experience while evaluating the histopathology of thymomas and staging these tumors. We will additionally glance over the clinical characteristics of these distinct tumors and the current management strategy.

The Co-Existence of Micronodular Thymoma and Lymphoma: A Clinicopathological and Immunohistochemical Study of Two Cases.

Two cases with the co-existence of micronodular thymoma and lymphoma are presented. The patients are two female patients 54 and 60 years of age who presented with symptoms of chest pain, general malaise, cough, and dyspnea. Diagnostic imaging demonstrated the presence of an anterior mediastinal mass. Initial biopsy was interpreted as an epithelial neoplasm compatible with thymoma. Surgical resection took place demonstrating the presence of micronodular thymoma in both cases. In addition, in both cases the lymphoid proliferation infiltrated surrounding adipose tissue. However, in one case the lymphoid proliferation was composed of atypical lymphocytes with irregular nuclei and increase mitotic activity positive for CD3 and TDT, while in the second case, the lymphoid proliferation was composed of more mature lymphocytes with a monocytoid appearance and positive for CD20. Both of these cases represent an unusual association and one that must be kept in the differential diagnosis especially in cases of micronodular thymoma.

Ligneous brochitis: A clinicopathological correlation of seven cases.

Seven patients with ligneous lesions of the bronchus are presented. The patients are five men and two women between the ages of 51 and 79 years (average: 65) who had prior history of pulmonary non-small cell carcinoma in the past 2-3 years. All the patients had undergone surgical resection followed by chemotherapy. The patients were evaluated for the potential recurrence of carcinoma and bronchial biopsies were obtained. Histologically, all the cases shared similar features, manly the presence of a subepithelial amorphous, acellular, eosinophilic material with minimal inflammatory reaction. Special histochemical stains for micro-organisms were negative as well as congo red for the presence of amyloid. No evidence of malignancy was seen in any of the biopsies. The current cases, represent an unusual histological feature that is more in keeping with ligneous bronchitis, possibly secondary to treatment.

Utility of Whole Slide Imaging for Intraoperative Consultation: Experience of a Large Academic Center.

CONTEXT.­: In the United States, review of digital whole slide images (WSIs) using specific systems is approved for primary diagnosis but has not been implemented for intraoperative consultation. OBJECTIVE.­: To evaluate the safety of review of WSIs and compare the efficiency of review of WSIs and glass slides (GSs) for intraoperative consultation. DESIGN.­: Ninety-one cases previously submitted for frozen section evaluation were randomly selected from 8 different anatomic pathology subspecialties. GSs from these cases were scanned on a Leica Aperio AT2 scanner at ×20 magnification (0.25 µm/pixel). The slides were deidentified, and a short relevant clinical history was provided for each slide. Nine board-certified general pathologists who do not routinely establish primary diagnoses using WSIs reviewed the WSIs using Leica Aperio ImageScope viewing software. After a washout period of 2-3 weeks, the pathologists reviewed the corresponding GSs using a light microscope (Olympus BX43). The pathologists recorded the diagnosis and time to reach the diagnosis. Intraobserver concordance, time to diagnosis, and specificity and sensitivity compared to the original diagnosis were evaluated. RESULTS.­: The rate of intraobserver concordance between GS results and WSI results was 93.7%. Mean time to diagnosis was 1.25 minutes for GSs and 1.76 minutes for WSIs (P < .001). Specificity was 91% for GSs and 90% for WSIs; sensitivity was 92% for GSs and 92% for WSIs. CONCLUSIONS.­: Time to diagnosis was longer with WSIs than with GSs, and scanning GSs and uploading the data to whole slide imaging systems takes time. However, review of WSIs appears to be a safe alternative to review of GSs. Use of WSIs allows reporting from a remote site during a public health emergency such as the COVID-19 pandemic and facilitates subspecialty histopathology services.

Thymic Carcinoma: A Review.

The diagnosis of thymic carcinoma may pose significant problems not necessarily in the histopathological diagnosis but rather in assigning the thymus as specific origin. Often the tissue available for interpretation is obtained via a mediastinocopic biopsy, which raises two different issues -minimal tissue and lack of specific features to make a carcinoma of thymic origin. In addition, if to that conundrum we add that there is no magic immunohistochemical stain that will unequivocally lead to the interpretation of thymic carcinoma, then we are left with a true clinical-radiological-pathological correlation. In this review, we will highlight some of those challenges that diagnostic surgical pathologists may encounter in the histopathological assessment of thymic carcinoma as well as in the staging of these tumors.

Primary Warthin's-like adenocarcinoma of the lung: A clinicopathological, immunohistochemical, and molecular analysis of three cases.

Three cases of primary pulmonary adenocarcinoma with prominent lymphoid stroma and papillary features mimicking Warthin's tumor are presented. The patients are two women and one man ages 52, 62, and 74 years respectively. Clinically, the patients presented with non-specific symptoms of cough, dyspnea, and chest pain. Imaging showed the presence of an intrapulmonary mass in the right lower, right upper and left lower lobe. All patients underwent lobectomy. Histologically, the tumors were characterized by the presence of and oncocytic papillary growth pattern embedded in a lymphoid rich background. Immunohistochemical stains for TTF-1, keratin 7, and beta-catenin were positive in the epithelial component, while CD20 showed strong positive staining in the lymphoid component. In addition, CD4 and CD8 also showed positive staining in a ratio of 3-4:1, EBER was negative. Kras mutations with wild type EGFR were identified in one case. Clinical follow-up ranging from 8 to 24 months was obtained showing that all patients are alive without recurrence. The cases herein presented represent an unusual histological variant of primary lung adenocarcinoma, which closely mimics Warthin's tumor.