Utility of the cytological criteria in the diagnosis of malignant pleural mesothelioma: Making the bridge between theory and practice.

INTRODUCTION: The diagnosis of malignant pleural mesothelioma (MPM) depends on microscopic examination performed on pleural biopsies taken under thoracoscopy. However, it has recently been established that cytology presents a significant diagnostic contribution enabling an earlier diagnosis with a minimally invasive procedure. AIM: To assess the diagnostic value of consensual cytological features of MPM in the differentiation between adenocarcinoma, mesothelioma and reactive mesothelial cells in pleural liquid. METHODS: All available retrospective records from the computerized pathology database system and pathology reports were searched for malignant pleural effusion cytology specimens, over a 5-year period from January 2015 to February 2020. The cytological criteria based on the international Guidelines for cytopathologic diagnosis of epithelioid and mixed type of MPM were assessed. Malignant mesothelial cells, MNML and RL were considered as the gold standard. RESULTS: 189 pleural biopsies with their corresponding cytology specimens were available for review. Among the reviewed cytologies, the diagnoses of 21/189 pleural cytologies were modified. The highest sensitivities were attributed to cytoplasmic blebbing, hypercellularity and cell ball clusters. The most specific feature was the absence of extracellular granular hyaluronic acid cores in reactive cytology and the absence of intercellular openings in NMML cell clusters. Extracellular granular hyaluronic acid cores had the highest positive predictive value and the highest negative predictive value was attributed to the cytoplasmic blebbing in both reactive cytology and NMML. CONCLUSION: These results highlight the fact that no sign is pathognomonic of the diagnosis of MPM pointing out the necessity of immunocytochemical techniques in equivocal cases.

Mediastinal cysts : a 52-case retrospective study.

INTRODUCTION: mediastinal cysts are rare lesions developed from mediastinal structures. They may be acquired like thoracic duct cysts or lymphangiomas or congenital like the bronchogenic cysts, enteric cysts or celomic cysts. These cysts are rare and may cause diagnostic challenges. AIM: To assess the major characteristics of these cysts based on a single institution experience. METHODS: the authors performed a descriptive, retrospective study from January 2009 to March 2020 in a single institution. Cystic lesions taking birth from the mediastinum for which gross features, microscopic features were available were included. RESULTS: this study contained 52 mediastinal cysts that were completely resected and no patient presented complications after the surgical resection. The bronchogenic cysts were the most frequent and represented 57.69% of all lesions. Thymic cysts and pericardial cysts represented respectively 40.38% and 1.92% of the cases. The positive diagnosis was based on the microscopic exam. The final diagnosis was concordant with the radiologic findings in 15 cases reaching a rate of 28%. CONCLUSION: the diagnosis of mediastinal cysts is based on the microscopic analysis of the cystic wall. Pericardial cysts may be suspected based on their characteristic location in the cardiophrenic angle, thymic cyst may be evoked based on their location in the thymic region and bronchogenic cysts are mainly located in the middle mediastinum. Inspite of these most frequent locations, the cysts may be located in any part of the mediastinum and may be difficult to diagnose when the key diagnostic features are absent.

Mediastinal paraganglioma as a large dumbell tumor: A case report.

Mediastinal paraganglioma presented as a large dumbbell tumor is a rare entity. We report a case of a 47 year old woman who suffered from spinal pain and sporadic lower limb paresis. The imaging studies showed a voluminous mass occupying the posterior mediastinum with right foraminal extension. For excellent results, a combined effort was necessary including thoracic and neurosurgeons teams. Complete resection was successfully performed without laminectomy. The operative course was uneventful.

Brucellar spondylodiscitis: A case series with focus on histopathological features.

Brucellar spondylodiscitis (BS) is the most common form of musculoskeletal brucellosis. The isolation of Brucella spp from blood, other body fluids or tissue cultures is the gold standard for definitive diagnosis of BS. BS shows a large histopathological spectrum of lesions with non-specific and granulomatous forms, and its histopathological features are not widely reported. This case series study reported the histopathological features of a series of 21 BS. Ten cases revealed nonspecific forms of BS. Lymphocytes were the predominant inflammatory cells in this group. In one case neutrophils were predominant. The eleven remaining were granulomatous. The 11 exhibited histiocytic type granulomas. Ten were non-necrotizing. One case, taken from abscess wall, contained minimal deposition of caseous like necrotic material. This case and 2 others corresponding to abscess wall biopsies, showed histiocytic granulomas mixed with small aggregates of epithelioid cells without well-formed epithelioid granuloma nor giant cell. The histopathological diagnosis of BS is challenging. Nonspecific forms of BS, mimiking pyogenic spondylodiscitis, are observed in about half of the cases. Although nonspecific forms of BS are characterized by the predominance of lymphocytes and plasmocytes, BS forms with predominant neutrophil cell infiltration do exist. Histiocytic granuloma is highly suggestive of BS. Purely epithelioid forms of BS were not observed in the present series. Caseous like necrosis suggestive of tuberculosis is a possible feature of BS.