Sputum characteristics of patients with severe COVID-19: report of two cases with immunocytochemical detection of SARS-CoV-2 spike protein.

Patients with SARS-CoV-2 infection and with severe COVID-19 often have multiple coinfections, and their treatment is challenging. Here, we performed cytology analysis on sputum samples from two patients with severe COVID-19. The specimens were prepared using the rubbing method and stained with Papanicolaou stain. In both cases, several cells with frosted nuclei were observed, and the cytological findings per 100 cells were evaluated. The infected cells were mononuclear to multinuclear, showing chromatin aggregation at the nuclear margins, intranuclear inclusion bodies, eosinophilic cytoplasmic inclusion bodies, and mutual pressure exclusion of the nuclei. Immunocytochemical staining revealed that the cells were positive for AE1/AE3 and negative for CD68 expression, indicating their epithelial origin. Furthermore, infected cells with frosted nuclei were positive for surfactant protein A (SP-A) in Case 2, suggesting infection of type II alveolar pneumocytes or Clara cells. Moreover, in Case 2, the infected cells were positive for herpes simplex virus (HSV) I + II and SARS-CoV-2 spike protein, confirming double infection in these cells. In conclusion, sputum cytology is an important tool for determining the diversity of viral infection, and additional immunocytochemistry can be used for definitive diagnosis.

Cytologic appearance of myospherulosis of the breast diagnosed by fine-needle aspirates: a clinical, cytological and immunocytochemical study of 23 cases.

The objective of this study was to introduce the clinical and cytological aspects of myospherulosis. A total of 5,174 consecutive breast fine needle aspiration (FNA) cytology cases were reviewed, among which 23 cases of myospherulosis of the breast were found, all in female patients. The main findings of myospherulosis, best seen with the Papanicolaou stain, consisted in the observation of spherules that were homogeneously smooth or contained one or more internal dense bodies. Routine Papanicolaou-stained slides with or without Romanowsky staining were analyzed. Immunocytochemistry was conducted for carbonic anhydrase 1 (CA1), glycophorin C, KP1, and PGM1. The patients' ages ranged from 41 to 79 years (mean age: 56 years). Of the 23 patients, 21 had a previous history of breast surgery. Cytologically malignant or suspicious diagnoses were made in four of the 23 cases. The size of parent bodies varied from 18.2 to 151 µm (mean, 52 µm). The size of spherules ranged from 2.1 to 16.4 µm (mean, 6.6 µm). Immunocytochemistry showed that the myospherules reacted with anti-CA1 and anti-glycophorin C antibodies. Most breast myospheruloses occur in patients with a history of breast surgery. Immunocytochemistry for CA1 and glycophorin C can enhance the diagnosis of myospherulosis.