Microcystic variant malignant mesothelioma presenting as a localized paraspinal mass

A 58-year-old man presented with productive cough and fever. Computed tomography (CT) scan of the chest showed an upper right paraspinal mass. CT-guided fine-needle aspiration biopsy showed lobules of vacuolated cells against a background of myxoid material. The cells demonstrated moderate to severe nuclear atypia and occasional mitoses. Immunohistochemistry revealed tumor cells to be immunoreactive for calretinin, WT-1, D2-40, cytokeratin (CK) 7, AE1/AE3, high molecular weight keratin, vimentin and epithelial membrane antigen, and negative for thyroid transcription factor-1, Ber-EP4, carcinoembryonic antigen, S100 protein, CK20, and CDX2. The combined morphologic and immunohistochemical findings confirmed the diagnosis of microcystic variant of localized malignant mesothelioma. The subsequent lung resection showed a pleural-based mass in the right upper lobe and confirmed the diagnosis. Awareness of the existence of unusual morphologic variants and localized forms of mesothelioma are necessary to avoid misdiagnosis of fine needle biopsy samples. Recognition of characteristic cytomorphologic features along with optimal use of panel of immunohistochemistry studies is crucial for making a specific diagnosis.

Microcystic Variant of an Intraosseous Meningioma in the Frontal Area: A Case Report

Meningiomas located inside the bone of the calvaria belong to the group of rare types of tumours. The microcystic variant is the least common in this area. Due to their similarity to other tumours in this area, the imaging test of those tumours may constitute the source of an improper preoperative diagnosis. According to the records of the Department of Neurosurgery in Bielsko-Biała, 133 patients diagnosed with an intracranial meningioma confirmed by a histopathological test were operated in the last 10 years (2004–2014). In the histopathological test, three patients were diagnosed with the microcystic variant, which constitutes 2.25% of the cases. Only one variant of microcystic meningioma was located inside the bone, which constitutes 0.75% of all the meningiomas operated.

Microcystic Variant of Urothelial Carcinoma

Background. Microcystic variant of urothelial carcinoma is one of the new variants of urothelial carcinoma that was added to the WHO classification in 2004.Aims.To review the literature on microcystic variant of urothelial carcinoma.Methods.Various internet search engines were used to identify reported cases of the tumour.Results. Microscopic features of the tumour include: (i) Conspicuous intracellular and intercellular lumina/microcysts encompassed by malignant urothelial or squamous cells. (ii) The lumina are usually empty; may contain granular eosinophilic debris, mucin, or necrotic cells. (iii) The cysts may be variable in size; round, or oval, up to 2 mm; lined by urothelium which are either flattened cells or low columnar cells however, they do not contain colonic epithelium or goblet cells; are infiltrative; invade the muscularis propria; mimic cystitis cystica and cystitis glandularis; occasionally exhibit neuroendocrine differentiation. (iv) Elongated and irregular branching spaces are usually seen. About 17 cases of the tumour have been reported with only 2 patients who have survived. The tumour tends to be of high-grade and high-stage. There is no consensus opinion on the best option of treatment of the tumour.Conclusions. It would prove difficult at the moment to be dogmatic regarding its prognosis but it is a highly aggressive tumour. New cases of the tumour should be reported in order to document its biological behaviour.