Variety Of Histological Changes Research Articles

Myopathy as a cause of fatigue in long-term post-COVID-19 symptoms: Evidence of skeletal muscle histopathology.

Background and purposeAmong post‐COVID‐19 symptoms, fatigue is reported as one of the most common, even after mild acute infection, and as the cause of fatigue, myopathy diagnosed by electromyography has been proposed in previous reports. This study aimed to explore the histopathological changes in patients with post‐COVID‐19 fatigue.MethodsSixteen patients (mean age = 46 years) with post‐COVID‐19 complaints of fatigue, myalgia, or weakness persisting for up to 14 months were included. In all patients, quantitative electromyography and muscle biopsies analyzed with light and electron microscopy were taken.ResultsMuscle weakness was present in 50% and myopathic electromyography in 75%, and in all patients there were histological changes. Muscle fiber atrophy was found in 38%, and 56% showed indications of fiber regeneration. Mitochondrial changes, comprising loss of cytochrome c oxidase activity, subsarcollemmal accumulation, and/or abnormal cristae, were present in 62%. Inflammation was found in 62%, seen as T lymphocytes and/or muscle fiber human leukocyte antigen ABC expression. In 75%, capillaries were affected, involving basal lamina and cells. In two patients, uncommon amounts of basal lamina were found, not only surrounding muscle fibers but also around nerves and capillaries.ConclusionsThe wide variety of histological changes in this study suggests that skeletal muscles may be a major target of SARS‐CoV‐2, causing muscular post‐COVID‐19 symptoms. The mitochondrial changes, inflammation, and capillary injury in muscle biopsies can cause fatigue in part due to reduced energy supply. Because most patients had mild–moderate acute affection, the new variants that might cause less severe acute disease could still have the ability to cause long‐term myopathy.

Fibroepithelial tumours of the breast-a review.

Fibroepithelial tumours of the breast are biphasic neoplasms composed of both epithelial and stromal elements, including the common fibroadenoma and the infrequent phyllodes tumour. The admixture of epithelium and stroma in the fibroadenoma shows intra- and pericanalicular patterns, and may display a variety of histological changes. Fibroadenoma variants include the cellular, juvenile, myxoid and complex forms. The cellular fibroadenoma may be difficult to distinguish from the benign phyllodes tumour. Stromal mitotic activity can be increased in fibroadenomas in the young and pregnant patients. Phyllodes tumours, neoplasms with the potential for recurrence, show an exaggerated intracanalicular growth pattern with broad stromal fronded architecture and stromal hypercellularity. They are graded into benign, borderline and malignant forms based on histological assessment of stromal features of hypercellularity, atypia, mitotic activity, overgrowth and the nature of the tumour borders. Classification of phyllodes tumours is imperfect, compounded by tumour heterogeneity with overlapping microscopic features among the different grades, especially in the borderline category. Malignant phyllodes tumours can metastasise and cause death. Determining which phyllodes tumours may behave aggressively has been difficult. The discovery of MED12 mutations in the pathogenesis of fibroepithelial tumours, together with other gene abnormalities in the progression pathway, has allowed refinements in diagnosis and prognosis.

Recurrent Schowannoma With Extensive Xanthomatous Changes: A Case Report

Schwannoma is one of the most common benign intracranial tumors, which originates from the Schwann cells of neural structures in the upper part of the vestibular branch of the eighth cranial nerve. This report describes a 64-year-old woman with headache and vertigo who had a past surgical history of acoustic schwannoma about 10 years ago. The patient underwent excisional surgery. Histological examinations revealed schwannoma with extensive xanthomatous changes. Immunohistochemistry staining confirmed the diagnosis. Base on the diagnosis, the patient received no more treatment. After 6 months of close follow-up examinations, no recurrence and complication were observed. Schwannoma could be seen with a vast variety of histologic changes. Recurrence of Schownnoma is uncommon in patients without neurofibromatosis, but it should be considered in a proper clinical context.

COVID-19 Vaccine & Bangladesh: New Year’s New Hope!!!

Melanocytic dysplasia refers not only to a variety of histologic changes, but is also a histologic diagnosis. Melanocytic dysplasia represents a diagnosis for those lesions in which the biologic potential cannot be determined. Histologic differences between a diagnosis of melanocytic dysplasia and malignant melanoma are detailed. The terms: borderline malignant melanoma or lesion, precancerous melanosis, active or activated nevus and atypical melanocytic hyperplasia should be abandoned. A differential diagnosis between in situ malignant melanoma and other melanin-containing in situ malignancies has been presented. All types of malignant melanoma which originate within the epidermis or epithelium have an in situ phase and show horizontal growth, and small early forms defy classification. The classification of the most common types of malignant melanoma has been revised. Although the level of invasion and tumor thickness are useful prognostic and therapeutic parameters, their determination is crude and subject to several shortcomings.

Histological changes associated with fibroadenoma breast

Introduction: Being the most common benign tumor of the breast, fibroadenoma show considerable histologic changes. It is important to highlight them as some of the changes are associated with increased risk of breast cancer. Aims and Objectives: To study the pattern and histologic changes in fibroadenoma breast. Materials and Methods: Retrospective analysis of histopathology of 55 cases of fibroadenoma breast diagnosed between Jan 2017 to Jun 2018. The pattern, epithelial and stromal changes were examined. Result: Commonest age group involved was in 3rd decade. Pericanalicular pattern was the predominant pattern. Apocrine and cystic change was the commonest change in epithelium. Two cases (3.6%) showed features of complex fibroadenoma. Three (5.5%) cases showed foci of tubular adenoma. Epithelial hyperplasia was seen in 5(9%) of cases of which 2 were mild, 2 were moderate and one was atypical hyperplasia. Inflammatory infiltrate in stroma was frequently observed. Conclusion: Fibroadenoma showed variety of histological changes of which complex fibroadenoma and epithelial hyperplasia are significantly important which requires appropriate management and follow up. Keywords: Fibroadenoma, Pattern, Histology, Changes.

Updates in staging and pathologic evaluation of esophageal carcinoma following neoadjuvant therapy.

Esophageal carcinoma comprises two major subtypes-squamous cell carcinoma and adenocarcinoma, the incidences of which vary widely across the world and also depend on the location within the esophagus. The staging of esophageal cancer (EC) also remains unique among various gastrointestinal carcinomas, as it takes into account the location, histologic type, and grade. Its management has been evolving over the years and the recent American Joint Committee on Cancer staging system has been updated to reflect the changing practice and new data. It is clear that preoperative neoadjuvant therapy is increasingly being used for the treatment of locally advanced esophageal carcinomas, followed by surgical resection that improves survival. A variety of histologic changes can be seen after neoadjuvant therapy, which can be challenging for the pathologists. The presence of residual tumor in the surgically resected specimen and lymph node following neoadjuvant therapy is associated with poor prognosis. Hence, a thorough pathologic assessment of tumor regression grade and accurate tumor staging is required by pathologists to provide valuable prognostic information to guide further management. Tumor regression grading in ECs needs to be improved and standardized.

HISTOLOGICAL STUDY ON THE EFFECT OF MORINGA OLEIFERA LAM ON THE DUODENUM OF ADULT RATS TREATED BY DIFFERENT DOSES OF DICLOFENAC SODIUM (VOLTAREN)

Diclofenac Sodium (DS) as one of Non-steroidal Anti-inflammatory Drugs (NSAIDS) is a commonly used and may be used in high or toxic doses by mistake or postoperatively. Consequently, the present study was designed to evaluate the possible protectiverole of Moringa Oleifera (MO) on the experimentally induced microscopical changes of duodenal mucosa of adult rats following administration of different high doses of DS. Forty five rats were divided into the following groups (15 each): Group I was served as a control group, Group II was subgrouped to IIa, b and c, that were administered oral 50, 100 and 150 mg/kg of DS respectively for 2 days after fasting for 20 hours. Group III was subgrouped to IIIa, b and c. These rats were maintained on oral MO (500mg/kg) daily for one week, and then they were administered the same doses as in the previous group. A variety of histological changes was observed in group II. The changes were ranged from loss of the brush border to cellular lysis, destruction of villi, monocellular infiltrations and basal glandular ulcerations. The PAS stained sections showed focal negative expression of the brush border together. Although the goblet cells appeared significantly decreased in number, they had increased acidic mucin secretion. In conclusion, the current study suggested that MO may have a limited and partial protective effect on the duodenal mucosa in cases of high dose administration.

Nonalcoholic Fatty Liver Disease: Pathologic Patterns and Biopsy Evaluation in Clinical Research

Nonalcoholic fatty liver disease (NAFLD) results in histologically complex specific and nonspecific injury patterns. In clinical research of NAFLD, the liver biopsy evaluation provides a wealth of information on the architectural arrangement and severity of a variety of histologic changes, including steatosis, inflammation, cellular injury, and fibrosis. This information is summarized as an overall diagnostic category, such steatosis or steatohepatitis and the severity of the injury can be graded and staged. Histopathologic disease classification in NAFLD is related to but separate from evaluation of individual histologic lesions. The patient population under study may affect the prevalence of histologic findings and in particular, pediatric patients with NAFLD may show a higher prevalence of zone 1 steatosis and periportal fibrosis as compared with adult populations. For the purposes of clinical research, it is important to provide the pathologist with biopsies that are adequate to classify the disease process as well as to grade and stage the changes. A current understanding of NAFLD pathologic classification, as well as nuances of grading and staging, is presented in this review.

Pathological Study of Secondary Glaucoma due to Congenital Syphilis-A New Theory of Vasculitis in the Schlemm’s Canal

Aims: To investigate histopathological changes in trabeculectomy (TLE) specimens in patients with secondary glaucoma due to congenital syphilis. Methods: Eleven eyes of 8 patients were used. The areas of TLE observed by gonioscopy were photographed before the surgery. Each of 13 TLE specimens (two eyes received TLE twice) were processed for light and transmission electron microscopy. Results: There was no inflammation in the anterior chamber at the time of TLE in any eyes. Gonioscopy showed a mixture of normal, thick pigmentation and peripheral anterior synechia. A variety of histological changes in the angle was observed among the samples or even in the same samples: normal (7 eyes) or occluded (8 eyes) Schlemm’s canal with (7 eyes) or without (4 eyes) inflammatory cells. These various changes were also observed in TLE samples taken from the same angle appearance observed by gonioscopy. Inflammatory cells were restricted to the area around the Schlemm’s canal and collector channels. Conclusion: Persistence of super-long-term inflammation in the angle might be the reason for the late onset of secondary glaucoma due to congenital syphilis. Infiltration of inflammatory cells around the Schlemm’s canal and collector channel despite no inflammation in the anterior chamber strongly suggested vasculitis of the Schlemm’s canal and collector channels. A variety of histological changes in the angle might be primarily caused by segmental inflammation of these vessels.

Flagellate Dermatitis as a Bleomycin-Specific Adverse Effect of Cytostatic Therapy

In oncology, bleomycin is a frequently used drug for the treatment of several malignancies. In particular, it is part of chemotherapy protocols in testicular cancer. We report on two patients with testicular cancer who received bleomycin-including chemotherapy and developed flagellate dermatitis. This is a typical adverse effect of bleomycin therapy; however, its pathophysiology has not yet been clarified. We discuss possible pathophysiologic mechanisms for this reaction. In general, it has been postulated that histopathologic findings in flagellate dermatitis share similarities with those observed in fixed drug eruptions. In fact, published cases in the literature have shown a broad variety of histologic changes and the histopathologic investigation of our two patients was not indicative of fixed drug eruption-like changes. Histology of one patient showed a superficial and deep, perivascular and periadnexal infiltrate of lymphocytes and eosinophils with a prominent perisudoral distribution, whereas the other patient was remarkable only for the presence of a rather sparse, superficial, perivascular lymphocytic infiltrate with occasional eosinophils and a few melanophages. Epidermal changes, in particular necrotic keratinocytes, were not present in either patient. We provide an overview of all reported histologic changes in bleomycin-induced flagellate dermatitis, including our experience with two patients. Based on these data, we present a summary of the clinical and histologic features.

Mortality of Centrarchid Fishes in the Potomac Drainage: Survey Results and Overview of Potential Contributing Factors

Skin lesions and spring mortality events of smallmouth bass Micropterus dolomieu and selected other species were first noted in the South Branch of the Potomac River in 2002. Since that year morbidity and mortality have also been observed in the Shenandoah and Monocacy rivers. Despite much research, no single pathogen, parasite, or chemical cause for the lesions and mortality has been identified. Numerous parasites, most commonly trematode metacercariae and myxozoans; the bacterial pathogens Aeromonas hydrophila, Aeromonas salmonicida, and Flavobacterium columnare; and largemouth bass virus have all been observed. None have been consistently isolated or observed at all sites, however, nor has any consistent microscopic pathology of the lesions been observed. A variety of histological changes associated with exposure to environmental contaminants or stressors, including intersex (testicular oocytes), high numbers of macrophage aggregates, oxidative damage, gill lesions, and epidermal papillomas, were observed. The findings indicate that selected sensitive species may be stressed by multiple factors and constantly close to the threshold between a sustainable (healthy) and nonsustainable (unhealthy) condition. Fish health is often used as an indicator of aquatic ecosystem health, and these findings raise concerns about environmental degradation within the Potomac River drainage. Unfortunately, while much information has been gained from the studies conducted to date, due to the multiple state jurisdictions involved, competing interests, and other issues, there has been no coordinated approach to identifying and mitigating the stressors. This synthesis emphasizes the need for multiyear, interdisciplinary, integrative research to identify the underlying stressors and possible management actions to enhance ecosystem health.

Histological assessment of the possible protective role of glimepiride against progression of experimentally induced diabetic nephropathy in rats

Introduction: little is known about the potential effects induced by sulphonylureas independently of their anti-hyperglycemic action. The present study examined the effect of glimepiride treatment on the progression of renal histological changes in diabetic rats to determine whether therapeutic intervention with these agents would prevent the onset and progression of renal complications or not. Material and methods: forty-eight adult male albino rats were equally divided into four groups; control, normal rats receiving glimepiride, streptozotocin induced diabetic non-treated rats and glimepiride-treated diabetic rats. Blood glucose level measurement and histological evaluation of renal tissue elements using H&E, Masson trichrome, and PAS reaction techniques at four and eight weeks after treatment were performed. Stained sections were subjected to some morphometric measurements namely, glomerular tuft area (GTA), mesangial matrix index (MMI) and area per cent of connective tissue (CT). Statistical analysis for significance of obtained data was performed using analysis of variance and student-T test. Results: Glimepiride did not cause any histological renal impairment when used solely. Induction of diabetes had a significant negative impact on renal structure. In addition to significant elevation of blood glucose levels, increased kidney and kidney to body weight ratio was estimated. A variety of histological changes affecting the glomerular and tubular elements of renal tissue were detected and were more intense in the eighth week of the experiment. A significant increase in GTA, MMI and area per cent of C.T. were also found in diabetic rats. All the tested parameters showed a significant improvement in the glimepiride-treated group. Conclusion: glimepiride could attenuate most of the histological changes produced in case of experimentally induced diabetic nephropathy in spite of persistent hyperglycemia. Recommendation: glimepiride could be used in Type I and type II diabetics to protect or slow down the progression of diabetic nephropathy.

Histological assessment of the possible protective role of glimepiride against progression of experimentally induced diabetic nephropathy in rats

Introduction: little is known about the potential effects induced by sulphonylureas independently of their anti-hyperglycemic action. The present study examined the effect of glimepiride treatment on the progression of renal histological changes in diabetic rats to determine whether therapeutic intervention with these agents would prevent the onset and progression of renal complications or not. Material and methods: forty-eight adult male albino rats were equally divided into four groups; control, normal rats receiving glimepiride, streptozotocin induced diabetic non-treated rats and glimepiride-treated diabetic rats. Blood glucose level measurement and histological evaluation of renal tissue elements using H&E, Masson trichrome, and PAS reaction techniques at four and eight weeks after treatment were performed. Stained sections were subjected to some morphometric measurements namely, glomerular tuft area (GTA), mesangial matrix index (MMI) and area per cent of connective tissue (CT). Statistical analysis for significance of obtained data was performed using analysis of variance and student-T test. Results: Glimepiride did not cause any histological renal impairment when used solely. Induction of diabetes had a significant negative impact on renal structure. In addition to significant elevation of blood glucose levels, increased kidney and kidney to body weight ratio was estimated. A variety of histological changes affecting the glomerular and tubular elements of renal tissue were detected and were more intense in the eighth week of the experiment. A significant increase in GTA, MMI and area per cent of C.T. were also found in diabetic rats. All the tested parameters showed a significant improvement in the glimepiride-treated group. Conclusion: glimepiride could attenuate most of the histological changes produced in case of experimentally induced diabetic nephropathy in spite of persistent hyperglycemia. Recommendation: glimepiride could be used in Type I and type II diabetics to protect or slow down the progression of diabetic nephropathy.

Study of Prostate of Korean Young Adult Using Transrectal Ultrasonography

Purpose: The prostate of the young adult is not a subject which has received much attention, and the vast majority of prostate studies have placed their emphasis predominantly on elderly patients. It seems, then, that an investigation of the prostate in younger patients is warranted, and perhaps long past due. Thus, we attempted to determine the mean prostate volume in Koreans in their 20’s. We also reported on the relationships between prostate size and body mass index, as well as body surface area, and compared the prostates of normal Korean youths with those of chronic prostatitis patients. Materials and Methods: Between March 2002 and February 2008, we chronicled 583 cases of transrectal ultrasonography (control group: 271, chronic prostatitis group: 314) and calculated prostate volumes via the biplane method. 178 of the cases in the chronic prostatitis group were again examined after treatment. In all of the cases, body mass index and body surface area were assessed. Results: The mean age of the patient was 22.83±2.46 years. The mean prostate volume of the 583 young adults was 15.58±3.11ml (control group: 15.61±3.16ml, chronic prostatitis group: 15.56±3.07ml). We ensured that there were no differences between the normal group and the chronic prostatitis group. The prostate volumes of the chronic prostatitis patients made no odds with the treated prostates. Additionally, prostate volume was directly proportional to the body mass index and the body surface area. Conclusions: The prostate volume of young Korean adults in their 20's was approximately 15.6ml. The development of chronic prostatitis in young men had no appreciable effect on prostate size, but was shown to induce a variety of histologic changes in the prostate, and these changes were similar to those observed in older patients. (Korean J Urol 2008;49: 720-726) 󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏

An Experimental Study of the Effects of Nicotine on the Intervertebral Disc

Backgrounds: Clinically it had been noticed that a large proportion of patients presenting with low back pain are smokers. Therefore, in this experimental study the histological effects of nicotine on the lumbar intervertebral discs of the rabbits was investigated. Material and Methods: Eighteen rabbits were divided equally into 3 groups, Group 1 (a & b); as control. Group2 injected intraperitoneally by 5000 ng/kg nicotine daily for 4 weeks. Group3 injected intraperitoneally by 5000 ng/kg nicotine daily for 8 weeks. The selected dose produced blood nicotine levels equivalent to those found in heavy smokers (30 cigarettes / day). Results: Light and electron microscopic studies revealed that nicotine injection showed a variety of histological changes, which were not observed in the control group. This includes appearance of spaces within the nucleus pulposus and separation from the adjacent fibrous lamellae in the annulus fibrosus. Also loss of the regularity of the multilayered structure of the annulus fibrosus, and excessive inclusions associated with vacuoles which continue with the rough endoplasmic reticulum within the chondrocytes. Disc degeneration was more marked in rabbits injected with nicotine for 8 weeks (G3) than in those injected for 4 weeks (G2). Conclusion: It could be concluded that the disc degeneration is more common among smokers and is correlated with the duration of exposure to nicotine.

An Experimental Study of the Effects of Nicotine on the Intervertebral Disc

Backgrounds: Clinically it had been noticed that a large proportion of patients presenting with low back pain are smokers. Therefore, in this experimental study the histological effects of nicotine on the lumbar intervertebral discs of the rabbits was investigated. Material and Methods: Eighteen rabbits were divided equally into 3 groups, Group 1 (a & b); as control. Group2 injected intraperitoneally by 5000 ng/kg nicotine daily for 4 weeks. Group3 injected intraperitoneally by 5000 ng/kg nicotine daily for 8 weeks. The selected dose produced blood nicotine levels equivalent to those found in heavy smokers (30 cigarettes / day). Results: Light and electron microscopic studies revealed that nicotine injection showed a variety of histological changes, which were not observed in the control group. This includes appearance of spaces within the nucleus pulposus and separation from the adjacent fibrous lamellae in the annulus fibrosus. Also loss of the regularity of the multilayered structure of the annulus fibrosus, and excessive inclusions associated with vacuoles which continue with the rough endoplasmic reticulum within the chondrocytes. Disc degeneration was more marked in rabbits injected with nicotine for 8 weeks (G3) than in those injected for 4 weeks (G2). Conclusion: It could be concluded that the disc degeneration is more common among smokers and is correlated with the duration of exposure to nicotine.

An Experimental Study of The Effects Of Nicotine on The Intervertebral Disc

Clinically it had been noticed that a large proportion of patients presenting with low back pain are smokers. Therefore in this experimental study we investigated the histological effects of nicotine on the lumbar intervertebral discs of the rabbits. Eighteen rabbits were used in this experiment. They were divided into 4 groups, 2 control groups G1a&G1b, and 2 treated groups G2 & G3. Groups 2 & 3were injected intraperitoneally by 500ug/kg nicotine daily for 4 or 8 weeks successively. The selected dose produced blood nicotine levels equivalent to those found in heavy smokers (30 cigarettes /day). Light and electron microscopic studies revealed that nicotine injection showed a variety of histological changes, which were not observed in the control group. This includes appearance of spaces within the nucleus pulposus and separation from the adjacent fibrous lamellae in the annulus fibrosus. Also loss of the regularity of the multilayered structure of the annulus fibrosus, and excessive inclusions associated with vacuoles which continue with the rough endoplasmic reticulum within the chondrocytes. Disc degeneration was more marked in rabbits injected with nicotine for 8 weeks (G3) than in those injected for 4 weeks (G2). This may indicate that the disc degeneration is more common among smokers and is correlated with the duration of exposure to nicotine.

Selective transvenous embolization for dural arteriovenous fistulas with the aid of superselective venograms of fistulous drainages and involved sinuses.

For the treatment of transvenous embolization (TVE) of dural arteriovenous fistulas (DAVFs) the sites of arteriovenous shunts, fistulous drainage, and the pathological changes inside the affected sinuses were explored in detail by means of preoperative arteriograms, superselective arteriograms, and superselective venograms. Out of 42 adult patients with DAVFs involving a total of 63 sinuses, three distinctive findings were identified as essential for indication of selective TVE for DAVFs. The first is extra-sinus fistulous drainage, which is embolizable fistulous drainage, remote from the major dural sinus, that flows into the sinus lumen. The second is intramural fistulous drainage, which is embolizable fistulous drainage located within the dural leafs of the involved sinus and separate from the major sinus lumen. The third consists of several lumens inside the affected sinuses, which suggests a variety of histological changes in the developmental process of sinus thrombosis and DAVFs. The extra-sinus drainage was occluded in three torcular heroplili fistulas and three transverse sinus fistulas. The intramural fistulous drainage was eliminated in three superior sagittal sinus fistulas. Several lumens inside the affected sinuses were encountered in 17 posterior fossa fistulas (68%) and 10 cavernous sinus fistulas (34%). These distinctive findings were recognized in 52% of the DAVFs. Out of various modalities for treatment of DAVFs, TVE has been the method of choice for the treatment of diffuse DAVFs. The TVE of DAVFs do not correspond to simple sinus occlusion, but imply selective occlusion of fistulous drainages and sinus lumens. The recognition of these three distinctive types of fistulous drainages have clinical impact in that it helps to completely occlude all the fistulous components of fistulas as well as preserve or restore the normal venous outflow through the involved sinus.

The canals of hering might represent a target of methotrexate hepatic toxicity.

Methotrexate treatment for psoriasis is known to cause hepatic fibrosis in some patients, which might progress to cirrhosis. The fine, radiating, fibrous septa developing in this setting have a distribution that is reminiscent of the location of the canals of Hering (coH). To assess the possibility of fibrous obliteration of the coH in patients receiving methotrexate, we developed a staining technique by combining an immunohistochemical stain for cytokeratin 7 with a modified Masson trichrome. Sixteen biopsy specimens from 7 patients were evaluated. The biopsies had a variety of histologic changes, including steatosis, anisonucleosis, multinucleation, chronic inflammation, bile duct damage, and ductular reaction. Fibrosis was present in 13 biopsy specimens (81%) and was mild in 7, moderate in 3, and severe in 3 specimens. Compared with normal (control) liver specimens, biopsy specimensfrom patients receiving methotrexate had decreased numbers of coH (1.9 +/- 0.8 vs 5.2 +/- 1.7; P < .025). In specimens with moderate or severe fibrosis, fibrous septa sometimes extended along the coH. These findings suggest that scarring of the coH might be a consequence of the toxic effects of methotrexate.

The Canals of Hering Might Represent a Target of Methotrexate Hepatic Toxicity

Methotrexate treatment for psoriasis is known to cause hepatic fibrosis in some patients, which might progress to cirrhosis. The fine, radiating, fibrous septa developing in this setting have a distribution that is reminiscent of the location of the canals of Hering (coH). To assess the possibility of fibrous obliteration of the coH in patients receiving methotrexate, we developed a staining technique by combining an immunohistochemical stain for cytokeratin 7 with a modified Masson trichrome. Sixteen biopsy specimens from 7 patients were evaluated. The biopsies had a variety of histologic changes, including steatosis, anisonucleosis, multinucleation, chronic inflammation, bile duct damage, and ductular reaction. Fibrosis was present in 13 biopsy specimens (81%) and was mild in 7, moderate in 3, and severe in 3 specimens. Compared with normal (control) liver specimens, biopsy specimens from patients receiving methotrexate had decreased numbers of coH (1.9 ± 0.8 vs 5.2 ± 1.7; P < .025). In specimens with moderate or severe fibrosis, fibrous septa sometimes extended along the coH. These findings suggest that scarring of the coH might be a consequence of the toxic effects of methotrexate.