Methenamine Silver Research Articles

Dual infection of maxillary sinus masquerading as a malignant lesion; A rare presentation

Primary sinonasal tuberculosis is a rare form of TB even in developing countries where TB is prevalent and invasive mycotic infection is more common in immunocompromised patients. It is unusual to have a dual infection with tuberculosis and mycosis in the maxillary region mimicking a neoplastic process and causing bone erosion. A 49-year old male presented with 2-year history of left-sided facial swelling. On microscopic examination, epithelioid cell granulomas, chronic inflammatory infiltrate, macrophages, giant cells, and focal necrosis were seen. Ziehl Neelsen staining for acid-fast bacilli with 20% H2SO4 was positive. Fungal hyphae were also seen in the sections examined. Special stains (Periodic acid-Schiff and Grocott’s methenamine silver stain) for fungal hyphae were positive. Mycosis and tuberculosis should always be considered in the differential diagnosis of maxillary lesions or sinusitis.

PAS Staining Variability in Fungal Infections of Skin

Abstract Introduction/Objective Developed in 1946 by J. F. A. McManus, the Periodic Acid Schiff (PAS) stain is among the most frequently used stains in histopathology as a cost-effective ancillary study for the detection of fungal organisms. Despite its wide use in dermatopathology, little research exists comparing PAS to its commonly used counterpart, Gomori methenamine silver (GMS), or to hematoxylin and eosin (H&E) alone. The variation in PAS staining between different fungi causing skin infections has been poorly studied. Methods/Case Report Eighteen cases of fungal skin infections from 1995-2023 were reviewed by a resident pathologist and attending medical mycologist. All eighteen cases possessed H&E, GMS, and PAS stains (staining preservation was confirmed). These cases were selected to represent the following categories of fungal skin infections: 1) superficial or cutaneous; 2) subcutaneous; and 3) systemic (including opportunistic mycoses and endemic dimorphic fungi). The following criteria were used to grade each specimen: ability of PAS to stain the organism’s cell wall; the demonstration of fungal morphology by PAS; and the ease of differentiating PAS-stained organisms from background compared to H&E alone. Results (if a Case Study enter NA) PAS allowed for ready visualization of fungal morphology for all organisms except for Histoplasma spp. and Blastomyces spp. in which organisms tended to blend in with background staining particularly in inflamed tissues. Both fungi were visualized better by GMS. The muriform bodies of chromoblastomycosis, while staining well with PAS, were easy to miss due to their tiny size. Conclusion Compared to H&E alone, PAS allowed for detection of organisms at a lower magnification (40X) for fungal infections except for those in chromoblastomycosis, histoplasmosis, and blastomycosis. PAS is a useful, cost- effective ancillary study for the detection of fungal organisms in dermatopathology; however, care must be taken when there is clinical suspicion for certain fungal organisms that are less well-visualized by PAS.

An idiosyncratic reaction to the synthetic biologic membrane on a surgical wound

Abstract Introduction/Objective Biodegradable temporizing matrix (BTM) is a synthetic polymer used to temporarily close wounds and aid the body in generating new tissue. BTM is applied to a debrided wound.BTM acts as a scaffold aiding the migration of granulation tissue into the matrix. Once the tissue is fully integrated throughout the BTM, the sealing membrane is removed. The matrix slowly deteriorates until fully absorbed at approximately 18 weeks. Methods/Case Report An 80-year-old woman with a past medical history of eczema, rheumatoid arthritis and gout presented with swelling of the left third metatarsal. Imaging showed an abscess which was eventually drained and cultured to show mycobacterium chelone. The patient was started on antibiotics for mycobacterium. On follow up she reported a nodule on left forearm recently increased in size. MRI on 9/28 showed abscess of the dorsal aspect of phalanx. She underwent surgical debridement 10/31 on her finger and the forearm nodule. After debridement a polynovo BTM graft was placed. Histopathology showed skin and subcutaneous tissue with necrotizing granulomas of the finger and the forearm. Cultures and stains for mycobacterium returned negative.The patient was subsequently followed up for wound healing. She reported nodules on the left forearm at the scar from previous surgical site which were biopsied. Histopathology showed granulomatous inflammation, rare foreign body giant cells, and birefringent material. The stains for Ziehl-Neelsen, Fite and Gomori’s Methenamine Silver for Urate Crystals were all negative excluding the possibility of gouty tophi or mycobacterium. Results (if a Case Study enter NA) NA Conclusion The complex history of the patient with mycobacterium, gout, the giant cell reaction and the unique appearing birefringent crystals presented a puzzling problem. Given the negative stain results for mycobacteria and the presence of birefringent (foreign) material, we deem these granulomas most likely an idiosyncratic reaction to the synthetic biologic membrane applied during her prior procedure. There are no known cases of giant cell reaction and similar morphology of birefringent (foreign) material in literature.

Diagnostic yield of stains for infectious organisms in esophageal or gastroesophageal junction biopsies with esophagitis*

ABSTRACT Stains frequently performed to exclude infectious etiologies in esophagitis include Grocott methenamine silver (GMS) and periodic acid–Schiff (PAS) as well as immunohistochemistry (IHC) assays for cytomegalovirus (CMV) and herpes simplex virus (HSV). The diagnostic yield of these tests, in this situation, has not been well studied. We retrospectively reviewed 261 esophageal biopsies, which had one or more of the above tests performed. The diagnostic yield for GMS and PAS was 8%, while CMV and HSV immunohistochemistry had a diagnostic yield of 1% and 0%, respectively. Our study suggests that routine use of ancillary labeling techniques in esophagitis biopsies may be of limited utility and have low diagnostic yield.

Evaluating the Efficacy of a Polymerase Chain Reaction Assay for Pneumocystis carinii Detection in Respiratory Samples

Abstract Introduction: Accurately identifying patients with pneumocystis pneumonia (PCP) presents considerable challenges, primarily relying on clinical suspicion. The manifestations of PCP lack specificity, encompassing symptoms such as cough, dyspnoea, fever, hypoxaemia, malaise and weight loss. Therefore, this study assesses the efficacy of a polymerase chain reaction (PCR) assay intended for use in clinical microbiology laboratories for the identification of Pneumocystis carinii from respiratory specimens. Materials and Methods: In this retrospective study, the medical records of patients aged 18 years and above were examined, focusing on those assessed using pneumocystis PCR-based tests. The study spanned from 2019 to 2022 in our tertiary care centre at Max Hospital, Saket. In this study, sputum and bronchoalveolar lavage (BAL) samples were proceeded for both staining and PCR for multi-copy mtLSU gene and single-copy dihydropteroate synthase polymorphisms (DHPS) fas gene of P. jirovecii. Results: In the analysis of 112 BAL specimens, 17 were identified as positive for P. carinii through both Grocott-Gomori’s Methenamine Silver Staining (GMS) staining and PCR. In addition, two BAL specimens were negative through GMS staining but showed positive results with PCR. On reviewing the clinical details of the patients associated with these two specimens, it was discovered that both individuals were under systemic steroid treatment, yet neither exhibited clinical signs of pneumocystis pneumonia (PCP). Consequently, these instances were classified as false positives by PCR. In comparison to GMS, the PCR assay demonstrated a sensitivity of 100% and specificity of 98% for detecting P. carinii in BAL specimens. Conclusions: The study underscores the necessity for individualised approaches, with each laboratory assessing the positive and negative predictive values based on their specific prevalence rates. In the ongoing pursuit of improving PCP diagnosis, PCR emerges as a promising screening tool that when used judiciously in conjunction with confirmatory measures, can enhance diagnostic precision in immunosuppressed populations.

Localized Pneumocystis jirovecii pneumonia in a malnourished, non-HIV-infected man in the absence of any established or diagnosed immunosuppressive condition: a case report

BackgroundPneumocystis jirovecii infection is an opportunistic infection that mostly affects patients with immunosuppressive conditions like human immunodeficiency virus (HIV) infection or medications, like corticosteroids. This study reports a rare case of Pneumocystis Jiroveci infection in a relatively immunocompetent patient which presented with uncommon radiological findings.Case presentationA 46-year-old man with a malnourished appearance and a history of opium dependence presented with dry cough, dyspnea, and weight loss to the hospital. There was no evidence of an immunocompromised condition or use of any immunosuppressive medication in the history of the patient. A lung high-resolution computed tomography (HRCT) scan revealed a crazy-paving appearance and localized infiltration. Methenamine silver staining and the histopathological findings in the transbronchial lung biopsy confirmed the diagnosis of PJP. Antibiotics and bronchodilators were administrated and the patient was discharged after 6 days of hospitalization. HIV testing and immunoglobulin levels were normal in the hospital course as well as his follow-up visits. After a 2-month follow-up, the patient was in good condition despite of mild remaining infiltration in his lung.ConclusionsPJP typically affects HIV-infected patients, but due to excessive use of immunosuppressive medications, its prevalence is increasing in non-HIV-infected patients. Malnutrition may predispose the patients to PJP, even in the absence of immunosuppressive conditions.

Spectrum of orbital fat necrosis in rhino-orbital-cerebral mucormycosis in post-COVID-19 patients.

Rhino-orbital-cerebral mucormycosis (ROCM) is the most common presentation of mucormycosis. Sinonasal-orbital debridement with exenteration is a life-saving procedure in ROCM patients in view of severe involvement of sinuses and the eyeball. Following the second wave of coronavirus disease 2019 (COVID-19), there was a massive surge in mucormycosis cases in India in post-COVID-19 patients. Of over 300 cases of mucormycosis admitted in our hospital, many underwent exenteration and these specimens were evaluated histopathologically, where fat necrosis was found to be a prominent finding. The spectrum of fat necrosis in ROCM in orbital fat has not been described in literature. Hence, we sought to evaluate the significance and spectrum of orbital fat necrosis in ROCM. This 3-month retrospective study included 15 cases of ROCM which underwent exenteration. Clinical data, radiologic details, and histopathologic findings were tabulated. Sections were also subjected to Periodic acid Schiff (PAS) and Gomori's methenamine silver (GMS) stains for confirming the fungus. All 15 cases showed fat stranding on computed tomography (CT) scan. On histopathologic examination, various tissue reaction patterns observed included acute/chronic inflammatory infiltrate, suppurative granulomas with giant cells, coagulative and fat necrosis, broad aseptate fungal hyphae with or without angioinvasion, and neural invasion. Fungal hyphae were confirmed with PAS and GMS stains. The spectrum of fat necrosis observed in all the cases included 1) acute necrotizing fat necrosis, 2) ghost adipocytes with or without saponification, and 3) crystalline/gouty fat necrosis. Fat necrosis is a significant finding in ROCM, both on CT scan and histopathology. All three patterns of fat necrosis may be observed simultaneously in a case of ROCM.

A review of lobomycosis and lobomycosis-like skin disease in cetaceans worldwide, with new data from the Gulf of Guayaquil, Ecuador.

Lobomycosis, also called paracoccidioidomycosis ceti, is a chronic mycotic cutaneous disease affecting odontocetes. Lobomycosis-like disease (LLD) has a clinical presentation consistent with lobomycosis but lacks a histological and molecular diagnosis. We review the literature on lobomycosis aetiology, clinical signs and pathogenesis, species affected and geographic distribution and examine the factors influencing the presence, transmission and prevalence of the disease, to better understand its ecology. In addition, we provide unpublished information on LLD in two common bottlenose dolphin (Tursiops truncatus) communities inhabiting the Gulf of Guayaquil, Ecuador. Lobomycosis and LLD occur in Delphinidae from the Atlantic, Pacific, and Indian Oceans between 33°N and 35°S. Primary risk factors include habitat, sex, age, sociality, and pollution. In dolphins from the Americas and Japan, lobomycosis is caused by Paracoccidioides ceti, family Ajellomycetaceae. The disease is characterized by cutaneous granulomatous lesions that may occur anywhere on the body, grow to large size, and may ulcerate. Histologically, the lesions consist of acanthosis and histiocytic granulomas between the skin and subcutaneous tissues, with inflammatory changes that extend deep into the dermis. Multiple yeast cells with a double refringent layer stained positive using Gomori-Grocott methenamine silver in the dermis of a T. truncatus from Ecuador diagnosed with LLD since 2011, a first record for the Southeast Pacific. Injuries may enable the entry of P. ceti into the dermis while skin contact likely favours transmission, putting males at higher risk than females. Lobomycosis and LLD may have a negative impact on small communities already threatened by anthropogenic factors.

Orbital Apex Syndrome Caused by Invasive Fungal Sinusitis due to Candida glabrata: A Case Report

Purpose: To report a case of orbital apex syndrome resulting from invasive fungal sinusitis attributed to the unusual <i>Candida glabrata</i> species.Case summary: A 76-year-old patient presented with persistent left-sided orbital pain, headaches, and blurred vision for 3 weeks. The patient had a history of uncontrolled diabetes, chronic kidney failure, and angina, and was treated for a COVID-19 infection 1 month prior to admission. Contrast-enhanced computed tomography scans revealed extensive bilateral sinusitis affecting the left optic nerve. The patient underwent endoscopic sinus surgery, which included nasal cavity biopsy, conducted by an otorhinolaryngologist. Histopathological analysis using Gömöri methenamine silver stains identified <i>Candida</i>. Cultures from sinus specimens later grew <i>Candida glabrata</i>. Treatment involved daily IV amphotericin B followed by oral itraconazole. After 6 months, the patient fully recovered from fungal sinusitis but continued to experience negative light perception in the left eye and progressed to complete ophthalmoplegia, consistent with orbital apex syndrome.Conclusions: Reports of invasive fungal sinusitis caused by <i>Candida</i> infections are rare globally. This report marks the first occurrence in this country. Effective management requires careful assessment and appropriate treatment tailored to the specific species, especially considering the risk of orbital extension of the inflammatory lesion.

Histopathological Alterations in Nilaparvata lugens (Hemiptera: Delphacidae) after Exposure to Cordyceps javanica.

The brown planthopper (BPH), Nilaparvata lugens (Stål, 1854), is a pest of rice plants worldwide. Cordyceps javanica is a destructive entomopathogenic fungus known to attack leafhoppers or BPHs specifically. Live adult BPH samples were inoculated with isolated C. javanica PSUC002, and their interaction was morpho-histologically examined from 0 to 120 h post-inoculation (pi). We observed that the mortality of BPH continuously increased until 120 h pi (Day 5). Tissue alterations in the host were examined after infection using morphological and histological methods, including the Grocott Methenamine Silver stain test (GMS). Filamentous fungi were first found on the external integument at 12 h pi, and fungal conidia attached to the integument at 24 h pi. However, the initial degeneration of BPHs was identified by histology at 6 h pi especially in the integument and adipose tissue. We identified the degeneration and loss of integument and adipose tissue of infected BPHs at 12 h pi, and their necrosis was completed at 96 h pi. The enzymatic index of the sampled fungi (chitinase and protease) peaked at 7 days of incubation. This study demonstrated that C. javanica PSUC002 is useful to control the BPHs as an eco-friendly practice and will possibly be applied in agriculture.

Severe Bilateral Sialadenitis of the Mandibular and Parotid Salivary Glands with Severe Panniculitis in a 2-Year-old Standard Poodle.

A 2-year-old male neutered Standard Poodle weighing 17.9 kg was presented to their primary care veterinarian for enlarged bilateral submandibular swellings following an interdog altercation sustained in the previous weeks. Cytology performed following fine-needle aspirates of the regions of swelling was inconclusive, and the patient was treated empirically with Clavaseptin. Despite treatment, the submandibular swellings continued to enlarge, and right-sided intermittent epistaxis was reported. On biochemical profile, there was mild hypercalcemia and mild hyperglobulinemia. The computed tomography (CT) findings were indicative of severe multifocal sialadenitis with severe regional cellulitis and inflammatory lymphadenopathy. Histopathology and cytology results described mixed inflammation of the salivary gland. Methenamine silver staining and Fite's acid-fast staining were negative. Aerobic and anaerobic cultures were negative. Targeted, next-generation DNA sequencing detected no known fungi or bacterial pathogens. These findings were consistent with the diagnosis of severe bilateral mandibular sialadenitis, panniculitis, and lymphadenopathy. The patient was prescribed enrofloxacin, clindamycin, phenobarbital, and prednisolone for 1 month. One week after initiating treatment, the patient had a significant reduction in size of the salivary glands. CT imaging was helpful in the diagnosis of this patient and allowed the clinician to identify which submandibular anatomical structures were abnormal, guiding subsequent diagnostic decisions to provide medical management to resolve the condition.

Histopathology of Allograft Nephrectomies – A Ten Year Observational Study

Background Though infrequent, allograft nephrectomies are performed for early and late graft loss. The study aims to analyze the histopathologic characteristics of allograft nephrectomy specimens. Materials and Methods We conducted an observational study of 103 cases of allograft nephrectomies from 21 centers from 2013 to 2023. All the pathology slides, including hematoxylin and eosin-stained sections, masson trichrome, jones methenamine silver, PAS, GMS, AFB, and immunohistochemistry (C4d, SV40) were reviewed. Pathologic findings were analyzed based on the transplant to nephrectomy interval (0–3 months, > 3 months) and type of donor (deceased, live donor). Results Of the total 103 cases, 77 were male. The mean age at the time of nephrectomy was 36.4 (range 5–64) years. The allografts were obtained from deceased (57) donors and live related (46) donors. Graft tenderness, oliguria/anuria, and fever were common clinical presentations. The majority (71.8%) of the nephrectomies were performed within the first 3 months of renal transplant. Renal vessel thrombosis (32.03%) was the most common pathologic finding. Infections were more common in the first 3 months after the transplant. Fungal infection had a significant association with deceased donor transplantation (p = 0.029). Conclusion Histopathological study of allograft nephrectomy specimens aids understanding of graft loss causes. The study also provides opportunities to prevent complications and implement measures to prolong graft survival in a subsequent transplant.

A decision support system for the detection of cutaneous fungal infections using artificial intelligence

Cutaneous fungal infections are one of the most common skin conditions, hence, the burden of determining fungal elements upon microscopic examination with periodic acid-Schiff (PAS) and Gomori methenamine silver (GMS) stains, is very time consuming. Despite some morphological variability posing challenges to training artificial intelligence (AI)-based solutions, these structures are favored potential targets, enabling the recruitment of promising AI-based technologies. Herein, we present a novel AI solution for identifying skin fungal infections, potentially providing a decision support system for pathologists. Skin biopsies of patients diagnosed with a cutaneous fungal infection at the Sheba Medical Center, Israel between 2014 and 2023, were used. Samples were stained with PAS and GMS and digitized by the Philips IntelliSite scanner. DeePathology® STUDIO fungal elements were annotated and deemed as ground truth data after an overall revision by two specialist pathologists. Subsequently, they were used to create an AI-based solution, which has been further validated in other regions of interests. The study participants were divided into two cohorts. In the first cohort, the overall sensitivity of the algorithm was 0.8, specificity 0.97, F1 score 0.78; in the second, the overall sensitivity of the algorithm was 0.93, specificity 0.99, F1 score 0.95. The results obtained are encouraging as proof of concept for an AI-based fungi detection algorithm. DeePathology® STUDIO can be employed as a decision support system for pathologists when diagnosing a cutaneous fungal infection using PAS and GMS stains, thereby, saving time and money.

Histoplasmosis: A case report

Histoplasmosis is common in certain regions of America, Asia and Africa. Cutaneous manifestation of Histoplasma capsulatum shows a wide spectrum of lesions. Histopathology plays a very important role in the detection and confirmation of diagnosis. Special fungus stains such as GMS (Gomori’s methenamine silver stain) and PAS (Periodic acid Schiff) stains can be used for its study.

Nonendemic rhinoscleroma: An unusual manifestation of the trachea.

Rhinoscleroma is classically described as a chronic granulomatous disease caused by Klebsiella rhinoscleromatis which primarily affects the nose and nasopharynx. When present, tracheal manifestations will be seen late in the disease course rather than on initial presentation. We describe a rare case of nonendemic rhinoscleroma that presented with tracheal lesions as an initial manifestation of disease. Case report and literature review. An 88-year-old male presented with longstanding dysphonia. Flexible laryngoscopy demonstrated a septal perforation and diffuse glottic lesions. CT neck demonstrated a nonobstructive polypoid tracheal lesion and mucosal thickening of the paranasal sinuses. Biopsy confirmed an atypical lympho-histiocytic proliferation and microorganisms within macrophages on Grocott methenamine silver and Steiner stains consistent with rhinoscleroma. He was referred for rheumatology and pulmonology consultation. Systemic diseases rarely affect the trachea, and even less frequently is a tracheal lesion identified as the initial manifestation of disease. The most common systemic diseases that affect the trachea include relapsing polychondritis, granulomatosis with polyangiitis, amyloidosis, and inflammatory bowel disease. The literature surrounding nasolaryngotracheal rhinoscleroma is limited, especially in nonendemic areas. It is necessary to include unusual etiologies of airway lesions in the differential diagnosis, which warrants comprehensive airway evaluation including biopsy. 4.

Unveiling the Uncommon: Gastrointestinal Basidiobolomycosis of the Colon and its Distinctive Splendore-Hoeppli Phenomenon

Background Basidiobolomycosis is a rare fungal infection caused by Basidiobolus ranarum. Case Presentation A 53-year-old man from Saudi Arabia with a known history of diverticulosis presented with severe abdominal pain and diarrhea. A CT scan revealed circumferential wall thickening of the descending and sigmoid colon with surrounding fat stranding, suggesting a diagnosis of complicated diverticulitis. Additional thick fluid was observed around the affected area. Surgical excision was pursued. A gross examination of two received large bowel segments disclosed marked ulcerated mucosa and wall thickening with exudate-covered serosal surfaces and adhesions. Microscopic examination unveiled significant infiltration by eosinophils, polymorphonuclear leukocytes, and granulomatous inflammation. Thin-walled, broad fungal hyphae of Basidiobolus, surrounded by eosinophilic material, were identified. Granulomas displayed abundant multinucleated giant cells and palisading histiocytes around central necrosis or abscess formation. Thin-walled, broad fungal hyphae of Basidiobolus, with sparse septations, are surrounded by a radiating, intensely eosinophilic cuff (Splendore-Hoeppli phenomenon). These hyphae, visible with hematoxylin and eosin staining, were further highlighted with periodic acid-Schiff and Gomori methenamine silver staining. Discussion Basidiobolomycosis may mimic neoplastic lesions. Histologically, the characteristic features include broad, thin-walled septate hyphae surrounded by eosinophilic material, a finding that is accentuated by the Splendore-Hoeppli phenomenon. Microscopic examination, along with special stains such as periodic acid-Schiff (PAS) and Gomori methenamine silver, is essential for accurate diagnosis. Conclusion Prompt recognition and appropriate antifungal therapy are vital for favorable patient outcomes. This report highlights the distinctive features of Basidiobolomycosis to raise awareness and understanding of this infrequent yet clinically significant fungal infection.

Fungi and bacteria occupy distinct spatial niches within carious dentin.

The role of bacteria in the etiology of dental caries is long established, while the role of fungi has only recently gained more attention. The microbial invasion of dentin in advanced caries especially merits additional research. We evaluated the fungal and bacterial community composition and spatial distribution within carious dentin. Amplicon 16S rRNA gene sequencing together with quantitative PCR was used to profile bacterial and fungal species in caries-free children (n = 43) and 4 stages of caries progression from children with severe early childhood caries (n = 32). Additionally, healthy (n = 10) and carious (n = 10) primary teeth were decalcified, sectioned, and stained with Grocott's methenamine silver, periodic acid Schiff (PAS) and calcofluor white (CW) for fungi. Immunolocalization was also performed using antibodies against fungal β-D-glucan, gram-positive bacterial lipoteichoic acid, gram-negative endotoxin, Streptococcus mutans, and Candida albicans. We also performed field emission scanning electron microscopy (FESEM) to visualize fungi and bacteria within carious dentinal tubules. Bacterial communities observed included a high abundance of S. mutans and the Veillonella parvula group, as expected. There was a higher ratio of fungi to bacteria in dentin-involved lesions compared to less severe lesions with frequent preponderance of C. albicans, C. dubliniensis, and in one case C. tropicalis. Grocott's silver, PAS, CW and immunohistochemistry (IHC) demonstrated the presence of fungi within carious dentinal tubules. Multiplex IHC revealed that fungi, gram-negative, and gram-positive bacteria primarily occupied separate dentinal tubules, with rare instances of colocalization. Similar findings were observed with multiplex immunofluorescence using anti-S. mutans and anti-C. albicans antibodies. Electron microscopy showed monomorphic bacterial and fungal biofilms within distinct dentin tubules. We demonstrate a previously unrecognized phenomenon in which fungi and bacteria occupy distinct spatial niches within carious dentin and seldom co-colonize. The potential significance of this phenomenon in caries progression warrants further exploration.

Histological Changes in Hepatocellular Carcinoma Post-locoregional Therapy

Locoregional therapies are widely practiced in treatment of primary hepatocellular carcinoma and metastatic carcinoma to the liver as they provide a more targeted treatment with lesser side effects. Transarterial chemo-embolisation and selective internal radiotherapy (SIRT) are a few examples. However, histopathological findings after locoregional therapy of hepatocellular carcinoma are rarely reported. We reported a case of a 61-year-old man with underlying Hepatitis B and subsequent hepatocellular carcinoma who was treated with SIRT followed by wedge liver resection. Macroscopically, the specimen showed a well-defined mass with areas of fibrosis and haemorrhage. Microscopic examination showed 70% tumour necrosis with numerous microspheres surrounded by multinucleated giant cells with histiocytes and chronic inflammatory cells. Currently, the patient is well with regular follow-up. The latest ultrasound findings showed no residual liver lesion in the background of liver cirrhosis. Although assessment of treatment response following locoregional therapy based on histopathological findings are not widely practiced, recognising histopathological changes such as tumour necrosis, provide valuable insight to a patient’s prognosis. Minimal to absent tumour necrosis implies poor response, limiting further locoregional therapy option. Findings of numerous microspheres might pose a diagnostic challenge as they mimic fungal organisms. Hence, histological examination with aid of special stains like periodic acid Schiff (PAS) and Grocott’s methenamine silver stain may be useful.

First confirmed case of equine pythiosis in Northern Veracruz, Mexico

A clinical case of an adult horse with invasive, ulcerative, proliferative, pyogranulomatous disease of the skin (tumor) in the shoulder region is presented. The mass had a granulomatous and crater-shaped appearance, with serosanguinous discharge and the presence of fistulas with caseous material. The tumor was removed by surgery and sent to the laboratory for diagnosis. Histopathology was performed using Grocott-Gomori methenamine silver stain. The presence of necrotic material, fibrosis, infiltrated cells, and brown-colored hyphae, characteristic of members of the genus Pythium, were observed. To identify the infecting species, conventional PCRs for the amplification of the ITS-1 was carried out. Histopathological and PCR tests confirmed infection by a Pythium insidiosum strain closely associated with previous records from the US and Central America. Our report represents the first molecularly confirmed case of equine pythiosis in Mexico.

Non-neoplastic Kidney Diseases in Adult Tumor Nephrectomy and Nephroureterectomy Specimens in a Southeast Asian Tertiary Medical Center

OBJECTIVE: Non-neoplastic kidney diseases are concurrently present in up to 15% of patients with renal and ureteral tumors, which have been most studied in the United States. This study was conducted to determine the prevalence and spectrum of renal parenchymal diseases in similar patients from a Southeast Asian academic institution.METHODS: We searched the database of the Department of Anatomical Pathology, Faculty of Medicine Vajira Hospital, Navamindradhiraj University (2012–2022) and found 194 adult nephrectomy and nephroureterectomy specimens with renal, renal pelvis, and ureteral tumors. Additional stains included periodic acid-Schiff, methenamine silver, and Masson trichrome. Direct immunofluorescence microscopy was performed on the paraffin tissue sections for immunoglobulin (Ig) G, IgA, IgM, and kappa and lambda light chains. Clinical information, including age, gender, and co-morbidities, was obtained from the electronic medical records.RESULTS: Analysis of the 194 cases demonstrated the average age was 61 years (range: 17-89 years), with 126 males (65%) and 68 females (35%). After re-examination of the non-neoplastic renal parenchyma, 14 cases (7%) had diffused and/or nodular mesangial sclerosis. Diabetic nephropathy (12 cases) and idiopathic nodular glomerulosclerosis (2 cases) were diagnosed and associated with either stage 1 or 2 genitourinary cancers. Another case was diagnosed with atheroembolic renal disease. In all cases, the concurrent renal diseases were not identified during the initial evaluation.CONCLUSION: Examination of the non-neoplastic renal parenchyma is important to identify non-neoplastic kidney diseases, such as diabetic nephropathy, so early treatment may result in improved clinical outcomes for kidney and urothelial cancer patients.