Rhinocerebral mucormycosis: Pathology revisited with emphasis on perineural spread.

AIMS AND OBJECTIVES: To study the histopathological features with particular emphasis on perineural invasion in invasive rhinocerebral mucormycosis. MATERIALS AND METHODS: Tissue sections from 30 patients with invasive rhinocerebral mucormycosis were included in the study. Demographic features, predisposing conditions, and clinical features were obtained from medical records. Tissue sections were reviewed with hematoxylin and eosin (H and E), Gomori's methenamine silver (GMS), and periodic acid Schiff (PAS) stains for (i) the presence and type of inflammation (suppurative/granulomatous; sparse/absent), (ii) invasion into soft tissues, and (iii) type of spread (angio/perineural) and presence of infarction/necrosis and fungal morphology. RESULTS: The study material included 20 males and 10 females with age ranging from 15-84 years. The clinical syndromes included rhino-orbital in 15, rhinocerebral in 6, and rhino-orbito-cerebral in 9 patients. On histopathological examination, inflammation was suppurative with predominance of neutrophils in 25 biopsies. Suppurating granuloma with neutrophils, lymphocytes, and foreign body giant cells was seen in 3 biopsies. Invasion into soft tissues, muscles, and adipose tissues was seen in 20 biopsies. Angioinvasion was noted in 25 and soft tissue invasion in 20 biopsies. Peripheral nerves were identified in 19 and perineural spread was identified in 15 biopsies. In all, biopsies with perineural invasion, angioinvasion, and soft tissue invasion were seen. CONCLUSIONS: Perineural invasion is one of the important histological features of invasive rhinocerebral mucormycosis and it indicates advanced the extent of invasion.

Malignant mesothelioma: A histomorphological and immunohistochemical study of 24 cases from a tertiary care hospital in Southern India.

BACKGROUND: Malignant mesotheliomas are histologically heterogeneous neoplasms. Definite diagnosis requires a varied panel of immunohistochemical (IHC) markers to differentiate these from histological mimics. Only a few case series have been reported in the Indian literature where mesotheliomas have been analyzed on routine histology and IHC. AIM: To evaluate the histological features of malignant mesothelioma and to elucidate the best possible immunomarker combination useful in different scenarios. MATERIALS AND METHODS: A total of 24 cases of malignant mesotheliomas of different sites encountered over a 6-year period were retrospectively analyzed with regard to their histomorphology and IHC findings. RESULTS: The pleura was the most common site of involvement (16 cases) followed by peritoneum (5 cases) and pericardium (3 cases). Epithelioid mesothelioma was the most common histological type (15 cases, 62.5%) followed by sarcomatoid (5 cases, 20.84%), deciduoid (2 cases, 8.34%), and 1 case each of desmoplastic and biphasic mesothelioma. Among the mesothelial markers, WT1 was positive in 17 of 20 (85%) cases and calretinin was positive in 20 of 21 (95.23%) cases. D2-40 and CK5/6 were positive in all cases where they were studied. Adenocarcinoma markers TTF-1, napsin A, and CEA had very high negative predictive value in ruling out mesothelioma. CONCLUSION: The differential diagnosis of mesotheliomas varies with histological type and tumor location. Judicious use of various combinations of IHC markers in different situation has been highlighted in this article.

Utility of immunochemistry in cytology.

BACKGROUND: The role played by cytology in primary diagnosis is undeniable. With improved management protocols and targeted therapy, the need for accurate diagnosis has become mandatory. Immunochemistry and molecular techniques are increasingly being used on limited tissue samples. AIMS: This study was conducted to find out the impact of immunocytochemistry (ICC) on cytology material in cytology practice. MATERIALS AND METHODS: Immunochemistry was done on alcohol-fixed smears and cell-block preparations. It was done with i6000 BioGenex autostainer using BioGenex reagents. RESULTS: A total of 148 cases occurring over a period of 3 years (September 2010-June 2013) were analyzed. Staining was done on cytology smears in 77 cases and on cell-block sections in 71 cases. ICC helped in diagnosis in 8 cases, confirmed the diagnosis in 26 cases, helped in subtyping in 60 cases, and helped in prognostication in 6 cases. ICC has altered the diagnosis in two cases. It was noncontributory in 43 cases, and the material was inadequate in three cases. CONCLUSION: In 102 cases (69%), ICC proved to be a useful adjunct in the diagnosis and prognostication; hence, its use is recommended in practice to aid in cytology services.