Toward interpretable and generalized mitosis detection in digital pathology using deep learning.

Objective: The mitotic activity index is an important prognostic factor in the diagnosis of cancer. The task of mitosis detection is difficult as the nuclei are microscopic in size and partially labeled, and there are many more non-mitotic nuclei compared to mitotic ones. In this paper, we highlight the challenges of current mitosis detection pipelines and propose a method to tackle these challenges. Methods: Our proposed methodology is inspired from recent research on deep learning and an extensive analysis on the dataset and training pipeline. We first used the MiDoG'22 dataset for training, validation, and testing. We then tested the methodology without fine-tuning on the TUPAC'16 dataset and on a real-time case from Shaukat Khanum Memorial Cancer Hospital and Research Centre. Results: Our methodology has shown promising results both quantitatively and qualitatively. Quantitatively, our methodology achieved an F1-score of 0.87 on the MiDoG'22 dataset and an F1-score of 0.83 on the TUPAC dataset. Qualitatively, our methodology is generalizable and interpretable across various datasets and clinical settings. Conclusion: In this paper, we highlight the challenges of current mitosis detection pipelines and propose a method that can accurately predict mitotic nuclei. We illustrate the accuracy, generalizability, and interpretability of our approach across various datasets and clinical settings. Our methodology can speed up the adoption of computer-aided digital pathology in clinical settings.

Prognostic significance of minor high grade component in non-invasive papillary urothelial carcinoma of urinary bladder: (A study of 273 consecutive cases over a period of 3 years).

PURPOSE: Our study aimed to determine the prognostic significance of minor high-grade components (HGC) in non-invasive papillary urothelial carcinomas compared with pure low-grade and high-grade tumors. MATERIAL AND METHODS: We retrospectively retrieved 273 in-house cases of non-invasive papillary urothelial carcinomas (pTa) from 2016 to 2018 for which follow up data was available in hospital archives. We stratified our data into four main groups (G). G1, pure low-grade (n = 164); G2, HGC ≤5 % (n = 17); G3, HGC >5 % to ≤25 % (n = 14); and G4, pure high-grade (n = 78). Prognosis was assessed in terms of recurrence, grade and stage of progression, metastasis, and death. The mean follow up duration was 34.72 ± 20 months (range 20-60 months). RESULTS: All four groups showed no difference in tumor recurrence (G1 81.7 %, G2 88.2 %, G3 92.9 %, G4 92.3 % p-value 0.183). In terms of grade progression, there was no significant difference in G2 35.3 % and G3 35.7 % and both groups showed worst prognosis compared to G1 16.5 % p-value 0.04. Regarding stage progression (G1 6.7 %, G2 23.5 %, G3 28.6 %, G4 41% p-value 0.001), metastasis (G1 5.5 %, G2 5.9 %, G3 7.1 %, G4 17.9 % p-value 0.01) and death (G1 4.3 %, G2 5.9 %, G3 7.1 %, G4 15.4 % p-value 0.02) there was no significant difference in G2 and G3 and both groups showed worst prognosis than G1 and better than G4. CONCLUSION: Urothelial carcinomas with minor high-grade component ≤25 % behaved worst than pure low grade and better than pure high grade and should be treated as distinct grade entity.

Survival outcomes of unilateral retinoblastoma based on pathological risk stratification-experience at a tertiary care centre in Pakistan.

Retinoblastoma (RB) is the most common childhood intraocular malignancy. In high-income countries over the past decade, upfront enucleation for unilateral RB is least favoured due to other alternatives that can help in globe preservation, but in low-middle income countries it is still the preferred option due to lack of resources and expertise. The treatment of RB after enucleation is tailored based on the histopathological risk features, as adjuvant chemotherapy with high-risk features reduces the risk of metastasis. The aim of our study was to analyse the survival outcomes of adjuvant therapy based on histopathological risk stratification in patients who underwent upfront enucleation for unilateral RB with advanced disease. A retrospective study was carried out at Shaukat Khanum Memorial Cancer Hospital and Research Centre, Pakistan. A total 113 patients (aged 3 months till 16 years) diagnosed with unilateral RB who had upfront enucleation from July 2009 till January 2019 were included in this study. The mean age of diagnosis was 37.4 months (±24.5) and male-to-female ratio of 1.3:1. The most common clinical presentation was leukocoria (74.3%). Patients who underwent enucleation had advanced disease; group D present in 62.8% followed by group E (32.7%). Histopathology revealed high-risk features in 29 patients (25.7%) and intermediate risk in 54 patients (47.8%). Disease progression and relapse was seen in patients with high-risk histopathological features. The 4-year over-all survival and EFS observed for this cohort was 74% and 71%. Awareness about the early symptoms among the general population and health care personnel at a nationwide level is needed to facilitate early detection and lessen disease related morbidity and mortality.

Expression Of Bap1 In Clear Cell Renal Cell Carcinoma.

BACKGROUND: BAP1 (BRCA1 associated protein 1 on chromosome 3) is a commonly mutated gene in clear cell renal cell carcinoma. Aim of the study was to evaluate the prognostic significance of BAP1 by immunohistochemistry in clear cell renal cell carcinoma. Methods: It was a descriptive case series in which data was retrospectively collected. Immunohistochemistry was used to evaluate the loss of nuclear expression of BAP1. RESULTS: Loss of BAP1 was observed in 60% of cases of clear cell renal cell carcinoma. 27% of grade 1 tumours, 62% of grade 2 tumours, 65% of grade 3 tumours and 66% of grade 4 tumours showed loss of BAP1. Loss of BAP1 was observed in 54% cases of stage 1 tumours, 72% of stage 2 tumours and 66% of stage 3 tumours. Our study showed loss of BAP1 in 67% of cases with tumour necrosis, in 75% of cases with sarcomatoid features and in 60% of patients with distant metastasis. Conclusion: We conclude that the loss of BAP1 nuclear expression is associated with poor prognostic features. i.e., higher grade, higher stage, tumour necrosis, sarcomatoid features and distant metastasis leading to death of patients.

Renal endometriosis: A benign disease with malignant presentation.

Endometriosis is a common gynecological disorder in which endometrial tissue is located outside the uterine cavity. Urinary tract involvement by endometriosis is uncommon. Renal endometriosis is a rare disorder and is not evident on imaging. It may be misdiagnosed as malignant disease and patients may undergo invasive procedures for it. We report a case of a young lady who presented with symptoms typical for renal mass, and was diagnosed as a tumor on imaging. Patient underwent radical surgery and histology revealed renal endometriosis.

Presentation of Acute Lymphoblastic Lymphoma and Colorectal Carcinoma in the Context of Constitutional Mismatch Repair Deficiency Syndrome: A Case Report with Literature Review.

Introduction: Constitutional mismatch repair deficiency (CMMRD) is a rare autosomal recessive disease carrying an increased risk of cancers (paediatric tumours of central nervous system, haematolymphoid malignancies along with gastrointestinal (GI) cancer(s), which are usually seen in the second and third decades), leading to syndromic presentation. Causal mutations are detected in DNA mismatch repair (MMR) genes, including MLH1, PMS2, MSH2 and MSH6 that are also known for their established role in Lynch syndrome. We describe a case of CMMRD with an earlier (first decade of life) presentation of mediastinal acute lymphoblastic lymphoma and colorectal malignancy. Case Presentation: A 5-year-old boy presented with respiratory complaints, bilateral cervical lymphadenopathy, multiple café-au-lait macules (CALMs) on the lower back and history of parental consanguinity with the death of three sisters due to brain tumour within 6 months of diagnosis. Computerised tomographic scan chest revealed a huge mediastinal mass. The patient underwent a trucut biopsy of the mass. The results were significant for a pre-T-cell acute lymphoblastic lymphoma. Suspicion of CMMRD was raised based on a combination of factors described above. A panel of MMR proteins was applied on the biopsy tissue that revealed loss of nuclear expression of MLH1 and PMS2 immunostaining in tumour cells with positive external controls. While on maintenance therapy for lymphoma, about a year later, the patient developed subacute intestinal obstruction due to a stenosing polypoidal circumferential tumour in the mid-sigmoid colon found on flexible sigmoidoscopy that was followed by endoscopic biopsies and insertion of a fully covered self-expanding metallic adult biliary stent with a diameter of 10 mm and length of 6 cm leading to immediate relief of obstruction. Biopsies revealed adenocarcinoma with neuroendocrine differentiation. Metastatic tumour deposits were seen in the omentum, anterior abdominal wall and the left peritoneal wall. Practical Implications: Earlier (first decade) presentation of GI malignancy warrants that an earlier screening through radiological scans for any possible tumours and MMR protein expression analysis (loss in tumour plus normal non-tumour cells) are essential in patients having CALMs and family history of paediatric tumours.

Sebaceous neoplasms: prevalence of HPV infection and relation to immunohistochemical surrogate markers.

BACKGROUND: Sebaceous neoplasms (SNs) and carcinomas (SCs) represent rare skin adnexal tumours. OBJECTIVES: To establish the prevalence of HPV in SNs, assess the relationship between HPV, p16 and p53 expression, and further elucidate the carcinogenetic course of SCs. MATERIALS & METHODS: A total of 113 resected SNs (five sebaceous adenomas, 10 sebaceomas and 98 SCs) from the Near-East were reviewed. Clinical information (age, gender, size and anatomical location), microscopic variables, and expression of several immunohistochemical markers (EMA, CK5/6, p63, p40, AR, p16 and p53) were documented. Cases were evaluated by fluorescently labelled PCR for HPV detection, followed by DNA microarray hybridization for subtype detection. RESULTS: HPV infection was detected in 9.4% of SNs: 28.6% sebaceous adenomas (HPV-16 and HPV-66), 9.1% sebaceomas (HPV-18) and 8.1% SCs. High-risk HPV types (HPV-16, -18, -52 and -66) constituted 90.9% of HPV infections. Histologically, HPV-positive SCs showed significantly milder cytologic atypia and patchy cellular necrosis. p16 was expressed in SNs irrespective of HPV status (20.0%, 33.3% and 65.5% of HPV-negative sebaceous adenomas, sebaceomas, and SCs, respectively), and p53 was abnormally expressed in 95.5% of HPV-negative SCs and all HPV-positive SCs. CONCLUSION: HPV infection is significantly present in benign and malignant SNs. HPV-positive SCs exhibit less cytologic atypia and necrosis than HPV-negative cases. p16 is not a surrogate marker of HPV infection in the SN setting. Further elucidation of various carcinogenic mechanisms in SCs will allow clinicians to single out the various populations at risk, optimize possible preventive strategies and develop targeted therapies.

PD-L1 expression in sebaceous carcinomas.

BACKGROUND: Traditional systemic treatments for unresectable, recurrent, and/or advanced sebaceous carcinoma (SC) are ineffective. Tumoral immune microenvironment characterization is essential for considering immune checkpoint inhibitors as a treatment option. METHODS: A total of 173 resected SCs were reviewed. Clinical information, lesion size, and location were collected. Microscopic examination documented histopathologic features and expression of immunohistochemical markers PD-L1 and CD8. PD-L1 percentage was assessed amongst tumor (PD-L1 + Tu) and immune infiltrating cells (PD-L1 + Inf). Each case was attributed a combined positive score (CPS) following Head and Neck squamous cell carcinoma recommendations. PD-L1 expression was evaluated according to clinicopathologic parameters. Human Papilloma Virus presence (HPV) was analyzed using PCR microarray scanning. RESULTS: A therapeutically relevant CPS was seen in 51.4% of cases. Higher PD-L1 + Tu, PD-L1 + Inf, and CPSs were positively associated with greater lesion size and an extraocular location. No association was seen with patient age or gender. 9.2% of SCs showed PD-L1 + Tu ≥ 1, while 52.0% showed PD-L1 + Inf ≥ 1. A higher CD8 + T-lymphocyte density was significantly associated with a higher CPS, PD-L1 + Tu, and PD-L1 + Inf. Tumor-associated T-cell infiltrate's density was higher along tumor periphery. HPV-16, HPV-43, HPV-52, and HPV-66 were detected in 8.4% of SCs. There was no significant association between HPV status, PD-L1 expression, and CPS. A significant number of SCs express PD-L1 at therapeutic levels. Nevertheless, PD-L1 expression shows a higher intertumoral heterogeneity, in extraocular than in biologically distinct periocular cases. CONCLUSION: Our data support the need for large-scale prospective studies evaluating anti-PD-L1 immunotherapy mainly in extraocular SC treatment.