RESUMO
BACKGROUND: Despite increasing interest in whole-slide imaging (WSI) over optical microscopy (OM), limited information on comparative assessment of various digital pathology systems (DPSs) is available. MATERIALS AND METHODS: A comprehensive evaluation was undertaken to investigate the technical performance-assessment and diagnostic accuracy of four DPSs with an objective to establish the noninferiority of WSI over OM and find out the best possible DPS for clinical workflow. RESULTS: A total of 2376 digital images, 15,775 image reads (OM - 3171 + WSI - 12,404), and 6100 diagnostic reads (OM - 1245, WSI - 4855) were generated across four DPSs (coded as DPS: 1, 2, 3, and 4) using a total 240 cases (604 slides). Onsite technical evaluation revealed successful scan rate: DPS3 < DPS2 < DPS4 < DPS1; mean scanning time: DPS4 < DPS1 < DPS2 < DPS3; and average storage space: DPS3 < DPS2 < DPS1 < DPS4. Overall diagnostic accuracy, when compared with the reference standard for OM and WSI, was 95.44% (including 2.48% minor and 2.08% major discordances) and 93.32% (including 4.28% minor and 2.4% major discordances), respectively. The difference between the clinically significant discordances by WSI versus OM was 0.32%. Major discordances were observed mostly using DPS4 and least in DPS1; however, the difference was statistically insignificant. Almost perfect (κ ≥ 0.8)/substantial (κ = 0.6-0.8) inter/intra-observer agreement between WSI and OM was observed for all specimen types, except cytology. Overall image quality was best for DPS1 followed by DPS4. Mean digital artifact rate was 6.8% (163/2376 digital images) and maximum artifacts were noted in DPS2 (n = 77) followed by DPS3 (n = 36). Most pathologists preferred viewing software of DPS1 and DPS2. CONCLUSION: WSI was noninferior to OM for all specimen types, except for cytology. Each DPS has its own pros and cons; however, DPS1 closely emulated the real-world clinical environment. This evaluation is intended to provide a roadmap to pathologists for the selection of the appropriate DPSs while adopting WSI.
RESUMO
BACKGROUND: Primary mediastinal germ tumours (PMGCT) constitute, a mere 3-4% of all germ cell tumours (GCT). Although they account for approximately 16% of mediastinal tumours in adults and 19-25% in children as per western literature, there is hardly any large series on PMGCT reported from the Indian subcontinent. DESIGN: We have retrospectively analysed clinicopathological features of 98 cases of PMGCT diagnosed over 10 years (2010-2019) from a tertiary-care oncology centre. RESULTS: The study group (n = 98) comprised predominantly of males (n = 92) (M:F ratio-15:1), with an age range between 3 months to 57 years (median: 25 years). The tumours were predominantly located in the anterior mediastinum (n = 96). Broadly, Non-seminomatous germ cell tumours (NSGCT) were more common (n = 73, 74%) compared to pure seminoma (n = 25, 26%). Mixed NSGCT was the most common histological subtype (n = 30) followed by pure mature teratoma (n = 18), pure Yolk sac tumour (n = 13), mixed seminoma and NSGCT (n = 5), pure immature teratoma (n = 3) and GCT; NOS (n = 4). Interestingly, all female patients had exclusive teratomas. Nine cases revealed secondary somatic malignancy (5 carcinomas and 4 sarcomas). The majority of patients received neoadjuvant chemotherapy (n = 71). Surgical excision was performed in 60 patients. Follow up was available in 68 patients. NSGCT showed a poor prognosis as compared to seminoma (p value = 0.03) and tumours with somatic malignancies had a more aggressive clinical course. CONCLUSION: PMGCT was seen predominantly in young adult males and somatic malignancies were noted in as high as 9% of cases. Patient with somatic malignancy have aggressive clinical course, hence, extensive sampling and careful histopathological evaluation are recommended for the identification and definitive characterization.