Clinical Differential Diagnosis Research Articles

Adding "Unlikely" as a Clinical Qualifier Is Unlikely to Be of Help: A Retrospective, Single-Center, Cross-Sectional Cohort Study.

Clinical correlation is essential to accurate and efficient diagnosis and differential diagnosis in dermatopathology. Poor-quality clinical information can lead to failures and delays in patient care. Some clinicians use the term "unlikely" when submitting a specimen. How frequently the "unlikely" clinical diagnosis correlates with the final pathologic diagnosis is unknown. We studied 203 dermatopathology reports from December 8, 2020, to July 1, 2021, that included the qualifier "unlikely" on the requisition sheet. Samples were stratified into either an inflammatory or neoplastic cohort based on final histopathologic diagnosis, with the neoplastic cohort being further stratified into pigmented and nonpigmented cohorts. Statistical analyses were conducted. The "unlikely" diagnosis in the clinical differential diagnosis and the final histologic diagnosis were the same in 7.9% of the 203 samples studied. This occurred in 8.5% of the inflammatory cohort and 7.6% of the neoplastic cohort. We concluded that the use of the qualifier "unlikely" is not helpful. We acknowledge the limitations of our study because of a small sample.

Line-Field Optical Coherence Tomography: Usefulness in the Non-Invasive Differential Diagnosis of Congenital Alopecia of Infancy.

Soon after birth, the clinical differential diagnosis between sebaceous of Jadassohn (NSJ), congenital triangular alopecia (CTA) and aplasia cutis congenita (ACC) may be challenging. A certain overlap of standard dermoscopic features can occur, especially in atypical cases, depending on scalp skin morphology and maturation age. The recently developed line-field confocal optical coherence tomography (LC-OCT) can provide morphological skin details with cellular resolution trough a rapid non-invasive examination. To assess the LC-OCT features of 6 cases of congenital alopecia of different aetiologies, with both typical and atypical clinical appearance. A non-invasive imaging examination combining standard dermoscopy, high-resolution videodermoscopy (HRVD) and LC-OCT was realized in 7 babies presenting for congenital alopecia with overlapping features, aged between 5 months and 5 years. Based on the specific LC-OCT features, and supported by HRVD features, a diagnosis of NSJ, congenital triangular alopecia (CTA) and AC) were made in 4, 2 and 1 case, respectively. The combined LC-OCT plus HRVD non-invasive imaging bring the advantage to have a real time diagnosis, to set the proper management and allows to avoid a skin biopsy in the perinatal age/first years of life at delicate skin site.

Lobar and Segmental Atrophy of the Liver: Differential Diagnoses and Treatments

Segmental or lobar liver atrophy is a common but not well-understood clinical condition. Hepatic atrophy can be classified into hepatic atrophy secondary to other pathologies and primary segmental hepatic atrophy, which is a benign intrahepatic lesion (pseudotumor) not associated with any other pathology. The pathophysiological mechanisms underlying atrophy can be divided into three main situations: obstruction of biliary outflow, obstruction of the systemic venous outflow, and obstruction of incoming portal venous flow. For what may concern secondary hepatic atrophy, there are many pathologies that could underlie this condition, ranging from benign to intrahepatic malignancies, with particular reference to particularly hepatocellular carcinoma and biliary duct carcinoma. An accurate and prompt differential diagnosis between the various forms and causes of atrophy is important for early identification and adequate treatment of underlying pathologies. A comprehensive review of the literature on the etiology and the radiological and histological characteristics of different types of hepatic atrophy is currently unavailable. Therefore, the aim of this review is to summarize the primary and secondary causes of segmental or lobar liver atrophy (excluding forms involving the entire liver parenchyma) and to provide practical tools for clinical and radiological differential diagnosis.

Gingival acquired lymphangiectasia as a long-term effect of post-oncology intervention: A 20-year institutional audit

Abstract Background: Gingiva is a keratinised mucosa akin to the skin and is exposed in all modalities of treatment of oral cancer. Acquired lymphangiectasia are acquired dilatations of lymphatic channels secondary to an external cause. They are extremely rare in the oral cavity despite that oral cancers are treated with different treatment modalities. Methods: The archives of the Oral and Maxillofacial Pathology Department of our institute were retrospectively reviewed from 2001 to 2021. Of the 9566 cases of oral biopsies, 4596 were confirmed cases of oral cancer including salivary gland carcinoma. These cases were followed up for the presence of post-neoplastic and post-therapeutic gingival lesions. Results: Of the 4596 patients, <10% patients reported recurrence or new primary of squamous cell carcinoma in the gingiva. Two patients were histopathologically diagnosed with acquired lymphangiectasia of gingiva after 12 years following surgery and radiation therapy as treatment for oral squamous cell carcinoma and mucoepidermoid carcinoma, which has been described in our report for the first time in the literature. Conclusion: Even though acquired lymphangiectasia of gingiva is very rare, lymphatic malformations should be included in the clinical differential diagnosis of post-therapeutic gingival proliferative pathologies in order to ensure appropriate treatment and prevent over-diagnosis of this benign condition.

Exploring the diverse phenotypes of anti-GAD 65 encephalitis, diagnosis and treatment challenges

Objectives. To present two cases of anti-glutamic acid decarboxylase 65 (anti-GAD65) antibody encephalitis with different clinical phenotypes. Introduction. Anti-glutamic acid decarboxylase 65 antibody encephalitis (GAD-65 AE) is a rare pathology with a high potential for severity, having multiple forms of presentation and multiple differential diagnoses. This presentation aims to exemplify the strong clinical heterogeneity that is associated with this clinical entity by putting forth two cases that were treated in our clinic, each representing a separate clinical phenotype of this pathology. Material and methods. We analyzed two cases from our clinic of autoimmune encephalitis with positive anti-GAD65 antibodies and compared the cases with the data from the literature regarding clinical presentation, differential diagnosis, treatment, and evolution. Content. The first case presented is a woman aged 71 (66 at onset) presenting with progressive cerebellar ataxia. She was diagnosed with GAD-65 AE based on clinical presentation and positive anti-GAD65 antibodies titer. She was initially treated with methylprednisolone pulse therapy and received four such courses in the first year after diagnosis, resulting in a slowing of the progression of the neurological deficit. During the COVID19 pandemic, treatment was paused and her neurological status resumed its decline, and she also developed insulin-dependent diabetes mellitus. Starting in 2021, treatment was continued, having received one course of IVIg and one course of plasma exchange in our clinic. Eventually, the treatment was switched to Mycophenolate mofetil but her status continues to decline. The second case is about a 32 years old woman, with a history of recurrent seizures and progressive memory decline that started at 28 years. She was diagnosed 11 months after the onset with limbic encephalitis with anti-GAD65 antibodies, left temporal focal epilepsy with nocturnal seizures and mild cognitive decline. She was treated with corticotherapy and IgG. She was discharged home with antiepileptic treatment with no recurring seizures, but a slow cognitive decline. She had two relapses at distance from the onset, the first one with status epilepticus and the second one with focal seizures and a generalized seizure. She developed type I diabetes with positive anti-pancreatic islet antibodies. After the first relapse, immunosuppressive therapy with Mycophenolate mofetil was initiated. The evolution was good and under immunosuppression she had only one episode of seizures in the context of a COVID-19 infection. Conclusions. Autoimmune encephalitis with positive GAD antibodies presents a very diverse clinical picture, as we can see in the presented cases.

The familiarity of Romanian psychiatrists with anti-N-methyl-D-aspartate receptor encephalitis: findings from a web-based survey study.

Psychiatrists are often the first to be consulted in patients with anti-N-methyl-D-aspartate receptor (anti-NMDAR) encephalitis. Thus, they need to be aware of clinical features, differential diagnoses, and treatment options for this condition. In this study, we aimed to investigate the familiarity of Romanian psychiatrists with anti-NMDAR encephalitis. We recruited psychiatrists from Romania and conducted a cross-sectional observational study by using a web-based survey. The survey was completed by 111 psychiatrists, of whom 47 (42.34%) were specialists, while 64 (57.66%) were trainees. The median length of training for specialists was ten years (interquartile range - IQR 9.5), while for trainees it was 2.5 years (IQR 3). In total, 31 (27.93%) psychiatrists encountered a case of anti-NMDAR encephalitis, with no significant difference between specialists and trainees. 31 (27.93%) psychiatrists were either unaware of the disorder or only knew its name, while 77 (69.37%) had knowledge of an outline of it. Only 3 (2.7%) psychiatrists had comprehensive knowledge of the disorder. Respondents with a higher awareness level had undergone significantly longer training (p=0.014). Unsurprisingly, having encountered a case significantly influenced awareness levels (p<0.001). There were no significant differences between specialists and trainees regarding specific knowledge about anti-NMDAR encephalitis. However, higher awareness levels and having encountered a case significantly influenced answer accuracy for questions regarding psychiatric presentation and epidemiological features. Our study indicates that Romanian psychiatrists have suboptimal knowledge of anti-NMDAR encephalitis, highlighting the need for improved awareness of this disorder.

Central Giant Cell Granuloma of the Mandible and Maxilla: A Clinicopathological Study of 21 Cases.

Background Central giant cell granuloma (CGCG) presents as a locally invasive, intraosseous lesion characterized by the accumulation of multinucleated giant cells amidst a matrix of hemorrhage and reactive fibrous tissue that infiltrates bone trabeculae. This idiopathic non-neoplastic proliferative lesion primarily affects the mandible, typically presenting as either unilocular or multilocular radiolucencies on X-rays. Although trauma or intraosseous hemorrhages are potential triggers, the precise histogenesis and etiology remain unclear. CGCG predominantly occurs in children and young adults, with a slight female predilection. Methods and materials A retrospective analysis of 21 cases of CGCG diagnosed at the Oral Pathology/Pathology department of Temple University Hospital between 2015 and 2022 was conducted. Each case was evaluated based on various parameters, including age, gender, presenting symptoms, radiographic findings, clinical differential diagnosis, and histological confirmation. The primary radiographic technique employed for diagnosis was X-ray imaging of the mandible and maxilla. The histological examination involved cutting paraffin-embedded tissue into 5-micrometer-thick sections, which were then stained using routine hematoxylin and eosin (H&E) stain. Notably, no specialized histochemical or immunohistochemical stains were utilized in the evaluation process. Results In our study, we reviewed 21 cases; 9 were male, 11 were female, and one had no available gender data.The age range was 15-76 years, with a mean of 50 years. The mandible was the most commonly affected location (17 cases; 81%)while the maxilla was less commonly involved (4 cases; 19%). Many CGCG lesions were asymptomatic (13 cases; 62%); eight cases (38%) were symptomatic, with painand fullness of the affected dental region being the main manifestations. In a few cases, conditions such as brown tumor (severe hyperparathyroidism) and odontogenic neoplasms, such as ameloblastoma, were suspected clinically and radiographically. The diagnosis of CGCG with associated acute and chronic inflammation was confirmed in all the cases. Histological evaluation of routinely stained slides was the main diagnostic tool utilized. No special stains or molecular studies were required to establish the final diagnosis. Conclusions Our investigation has determined that CGCG exhibits a non-neoplastic nature, displaying a spectrum of behaviors ranging from non-aggressive to aggressive tendencies. While CGCG is predominantly observed in the mandible, rare instances of involvement in the maxilla have also been documented. Importantly, no confirmed association with neoplastic lesions was identified during our analysis. The clinical course of CGCG tends to be indolent, with some cases presenting in association with impacted teeth. It's noteworthy that CGCG can present features mimicking neoplastic conditions, such as ameloblastoma, or localized lesions linked to systemic disorderssuch as hyperparathyroidism (brown tumor).

Unusual etiology of anterior knee pain in a young athlete engaged in chronic jumping exercises: The intratendinous ganglionic cyst of the patellar tendon

Intratendinous ganglionic cysts within the patellar tendon represent an exceedingly rare pathological entity, the clinical presentation of which is poorly understood and infrequently reported. We present a comprehensive case report of a young male athlete with persistent anterior knee pain, which was ultimately attributed to the presence of an intratendinous ganglionic cyst within the patellar tendon. This report provides a detailed analysis of the clinical presentation, radiological findings, differential diagnoses, and management strategies in the context of this rare condition.

Challenges in differential diagnosis and treatment of cervical root resorption vs. root caries.

External cervical root resorption may be occasionally mistaken for root caries and vice versa. Radiographical and clinical differential diagnoses of cervical root resorption and root caries are essential for correct treatment planning and a successful treatment outcome. This article reviews the contemporary literature and summarises the prevailing professional consensus pertaining to external cervical root resorption. Clinical diagnostics which help distinguish cervical root resorption from root caries are outlined and treatment approaches of external cervical root resorption are discussed.

China Anti-Cancer Association Guidelines for the diagnosis, treatment, and follow-up of thymic epithelial tumors (2023).

Thymic epithelial tumors (TETs) are a relatively rare type of thoracic tumors with higher incidence in Asians. The diagnosis and treatment pattern has long been based mainly on clinical experience and expert consensus. In recent years, with an increasing number of TETs detected in physical examinations, there is an urgent need to develop the guidelines that apply to the Chinese population. Thus, we intend to develop a holistic integrative guideline for TETs. Under the leadership of the Chinese Anti-Cancer Association (CACA) Mediastinal Tumor Committee, a multidisciplinary guideline development group was established. Systemic literature review and two rounds of questionnaires regarding key clinical issues were carried out. The grading of recommendations assessment, development and evaluation (GRADE) approach was used to rate the quality of evidence and the strength of recommendations. The CACA guideline provides recommendations for the clinical differential diagnosis of anterior mediastinal lesions, management of asymptomatic small anterior mediastinal nodules, pathological classification and staging systems of TETs, as well as principles of surgery, neoadjuvant and adjuvant therapies, systemic therapies for advanced TETs, and follow-up strategies after surgical resection. This guideline provides holistic integrative management strategies for TETs and would be a useful tool for clinicians on decision-making.

Multidimensional assessment of social cognition using non-immersive virtual reality in dementia with Lewy bodies and Alzheimer’s disease: an exploratory study

ABSTRACT Introduction Few studies have focused on social cognition in dementia with Lewy bodies (DLB), even though some brain structures being well known as underlying social cognitive processes are directly impacted in this disease. Furthermore, social cognition processes have been mostly studied independently using evaluations with poor ecological validity. We aimed at studying the ability of a new naturalistic and multidimensional social cognition task to reveal impairments in DLB patients. We chose to compare the profile of these patients with that of Alzheimer’s disease (AD) patients, for which social cognition is better preserved. Method Fifteen patients (DLB: n = 7; AD: n = 8) and 28 healthy controls underwent the REALSoCog task. They encountered several social situations (e.g. control versus transgressions) in a non-immersive virtual city environment allowing the assessment of moral cognition, cognitive and affective theory of mind (ToM), emotional empathy and behavioral intentions. Results The main results showed (i) a lower ability to detect transgressions in DLB patients, particularly conventional ones, whereas moral cognition seemed better preserved in AD patients; (ii) a cognitive ToM impairment in both DLB and AD patients, while affective ToM is impaired only in DLB patients; (iii) a decreased emotional empathy specifically observed in DLB patients; (iv) more inappropriate behavioral intentions, mainly in DLB patients, but also in some AD patients. Conclusions This study suggests the feasibility and potential interest of the REALSoCog task in revealing social cognition deficits, particularly for DLB patients by showing different social patterns as compared to AD patients. These results offer interesting clinical perspectives to develop more naturalistic tasks in such populations and for clinical differential diagnosis. Limitations and future perspectives are discussed.

Abnormal resting-state EEG phase dynamics distinguishes major depressive disorder and bipolar disorder

Changes in EEG have been reported in both major depressive disorder (MDD) and bipolar disorder (BD). Specifically, power changes in EEG alpha and theta frequency bands during rest and task are known in both disorders. This leaves open whether there are changes in yet another component of the electrophysiological EEG signal, namely phase-related processes that may allow for distinguishing MDD and BD. For that purpose, we investigate EEG-based spontaneous phase in the resting state of MDD, BD and healthy controls. Our main findings show: (i) decreased spontaneous phase variability in frontal theta of both MDD and BD compared to HC; (ii) decreased spontaneous phase variability in central-parietal alpha in MDD compared to both BD and HC; (iii) increased delays or lags of alpha phase cycles in MDD (but not in BD), which (iv) correlate with the decreased phase variability in MDD. Together, we show similar (decreased frontal theta variability) and distinct (decreased central-parietal alpha variability with increased lags or delays) findings in the spontaneous phase dynamics of MDD and BD. This suggests potential relevance of theta and alpha phase dynamics in distinguishing MDD and BD in clinical differential-diagnosis.

#2984 SLE associated fibrillary glomerulonephritis vs SLE nephritis with fibrils: can a straightforward distinction always be made?

Abstract Background and Aims Fibrillary glomerulonephritis (FGN) is an uncommon but serious kidney disease with unclear aetiology, variable prognosis, and a not well-established treatment. FGN has been associated with autoimmune diseases including SLE. Other aetiologies comprise diabetes, malignancies, HCV and chronic infections. Our goal is to discuss the pathologic and clinical differential diagnosis conundrums that a patient with a suspected SLE presented. Method We present the case of a 53-year-old woman evaluated for proteinuria (1 g/24 h), and glomerular haematuria. Renal function was normal. She referred mild arthralgias for the past two years. Her medical history was unremarkable for diabetes and hypertension. ANA and anti-dsDNA were positive. The rest of the immunological work-up was normal as well as protein immunofixation/free light chains. HCV, HBV, and HIV serology was negative. A thorough evaluation for malignancy was negative. A renal biopsy was performed. Results The renal biopsy showed enlarged glomeruli with mesangial matrix expansion (Congo-red negative), mild mesangial hypercellularity and focal endocapillary hypercellularity without hyaline deposits, fibrinoid necrosis or crescents, without significant chronic lesions (Fig. 1). A probable diagnosis based on light microscope could be that of a lupus nephritis class III with low activity and low chronicity indices. Immunofluorescence demonstrated weak or moderate immunofixation of IgG (2+), IgA(1+), C3(2+), C1q(1+), κ(1+) and λ(1+) in the mesangium and segmentally in the capillary walls with a smudgy appearance. IgM, C4, fibrinogen and albumin were negative. The lack of a full-house pattern and, more significantly, the low C1q intensity raised some questions about the validity of a lupus nephritis diagnosis. Ultrastructural evaluation revealed abundant fibrils that occupied the mesangium and permeated the glomerular basement membranes (GBMs). Fibrils were non branching and randomly oriented with a mean diameter of ∼15 nm (range: 11,87 nm -18,84 nm) (Fig. 2). No electron dense deposits, fingerprint deposits or tubuloreticular inclusions were detected. Immunohistochemical staining for DNA-J heat-shock protein family member B9 (DNAJB9) was then performed showing strong positivity in the mesangial matrix and GBMs. Interestingly, C4d was also strongly positive with the same pattern as DNAJB9. The diagnosis of fibrillary glomerulonephritis was suggested, mostly based on ultrastructural evaluation and immunohistochemical findings. Conclusion It is well known that the characteristic features of lupus nephritis (intense C1q staining, full-house staining, extraglomerular deposits, tubuloreticular inclusions, and combined subendothelial and subepithelial deposits) are, in some cases, neither universally present nor specific for lupus nephritis. Of special interest is the identification of fibrils in the renal biopsy of an SLE patient. The crucial importance of distinguishing between SLE associated FGN and SLE nephritis with fibrils is based on the generally poor renal prognosis of FGN as well as the unsatisfactory performance of immunosuppression. The differential diagnosis can be very challenging especially when DNAJB9 is not available.

Electrochemical Sensor for the Detection and Accurate Early Diagnosis of Ovarian Cancer.

Ovarian cancer (OC) has the highest mortality rate among malignant tumors, primarily because it is difficult to diagnose early. Exosomes, a type of extracellular vesicle rich in parental information, have garnered significant attention in the field of cancer diagnosis and treatment. They play an important regulatory role in the occurrence, development, and metastasis of OC. Consequently, exosomes have emerged as noninvasive biomarkers for early cancer detection. Therefore, identifying cancer-derived exosomes may offer a novel biomarker for the early detection of OC. In this study, we developed a metal-organic frameworks assembled "double hook"-type aptamer electrochemical sensor, which enables accurate early diagnosis of OC. Under optimal experimental conditions, electrochemical impedance spectroscopy technology demonstrated a good linear relationship within the concentration range of 31-3.1 × 106 particles per microliter, with a detection limit as low as 12 particles per microliter. The universal exosome detection platform is constructed, and this platform can not only differentiate between high-grade serous ovarian cancer (HGSOC) patients and healthy individuals but also distinguish between HGSOC patients and nonhigh-grade serous OC (non-HGSOC). Consequently, it provides a novel strategy for the early diagnosis of OC and holds great significance in clinical differential diagnosis.

Correction: Peripheral ulcerative keratitis: Clinical characteristics, differential diagnoses and therapeutic concepts

Correction: Peripheral ulcerative keratitis: Clinical characteristics, differential diagnoses and therapeutic concepts

Pilomatrixomas: 31 years of experience in population under and over 18 years of age.

Pilomatrixoma, also known as calcifying epithelioma of Malherbe, is a benign cutaneous neoplasm that demonstrates differentiation towards the matrix portion of hair follicles. It is the most common benign cutaneous neoplasm in childhood and youth, although it can occur at any age. With a general incidence ranging from 0.001% to 0.0031% of all cutaneous tumors. There is a slight predilection for females, with a female-to-male ratio of 1.15:1. Observational, descriptive, retrospective, and cross-sectional study conducted using the electronic database of the dermatopathology department of Dr. Manuel Gea González General Hospital, from January 1992 to July 2023. Only cases with a histopathological diagnosis of pilomatrixoma, pilomatricoma, and Malherbe's calcifying epithelioma were included. A total of 200 pilomatrixomas were recorded in 177 patients. The tumor predominantly affected females in the pediatric age group, with an average age of 22.98 years in the studied population. The most common location was the head (periorbital region), followed by the upper extremities and trunk. Upon separating the population into pediatric and adult groups, 111 and 89 cases were identified, respectively. We present a detailed study on pilomatrixomas with a comprehensive overview of the demographic, clinical, and epidemiological characteristics of this benign cutaneous neoplasm. The results revealed robust statistical data highlighting the distribution by age, gender, topography, morphology, accompanying symptoms, and frequency of clinical differential diagnoses. This study significantly contributes to the existing knowledge of pilomatrixomas and serves as a valuable reference for future research and clinical practice.

Liver non-contrast perfusion in diffuse liver diseases diagnostic algorithm: the new diagnostic criteria

Purpose: to define the new criteria for contrast-free ASL perfusion using for the management of diffuse liver diseases (DLD).Material and methods. Clinical and laboratory data, results of MRI with non-contrast MR perfusion (ASL-perfusion) of the liver were estimated in a group of patients with DLD (three-year research).Results. Potentials of assessment of liver ASL perfusion for patients with DLD (including complicated cases) are described in the article. It was established that ASL liver perfusion is useful for DLD clinical forms differential diagnosis, predicting the risk of liver cirrhosis, as well as complications (hepatic encephalopathy, sialoadenitis) and DLD exacerbation. The strategy of contrast-free MR perfusion using in patients with DLD management algorithm was developed.Conclusion. Liver ASL perfusion is a promising for the study and application method for the management of DLD.

When mycosis fungoides seems not to be within the spectrum of clinical and histopathological differential diagnoses.

The most prevalent primary cutaneous T-cell lymphoma, mycosis fungoides (MF), is characterized by the development of plaques and nodules after an erythematous patchy phase that is non-specific. An infiltrate of atypical small- to medium-sized cerebriform lymphocytes in the superficial dermis, with variable epidermotropism, is the histopathological hallmark of the disease. In more advanced stages of the illness, large-cell transformation may be seen. Early diagnosis of MF can be very challenging based only on histopathologic or clinical findings, so it is critical to have a clinical-pathological correlation. Many atypical variants of MF that deviate from the classic Alibert-Bazin presentation of the disease have been described over the past 30 years, sometimes with different prognostic and therapeutic implications. Clinically or histopathologically, they can mimic a wide range of benign inflammatory skin disorders. To make a conclusive diagnosis in these cases, it is recommended to take multiple biopsies from various lesions and to carefully correlate the clinical and pathological findings. We have outlined the various facets of the illness in this review, positioning MF as a "great imitator", with an emphasis on the more recently identified variations, differential diagnosis, and its benign mimics.

Clinical progression and differential diagnosis of an uncommon delayed-onset thyroid eye disease in a patient with graves' disease: a case report

Clinical progression and differential diagnosis of an uncommon delayed-onset thyroid eye disease in a patient with graves' disease: a case report

Expression of Fascin-1 and its diagnostic value in liver cancer

Although some studies have reported on the expression and clinical significance of Fascin-1 (FSCN1) in liver cancer, the clinical application and differential diagnosis value of FSCN1 in liver cancer are still unclear. The aim of this study was to analyze the expression level of FSCN1 protein in liver cancer tissues and explore its diagnostic and application value in differentiating between hepatocellular carcinoma (HCC) and intrahepatic cholangiocarcinoma (ICC). The immunehistochemical analysis was used to detect the expression of FSCN1 in 108 cases of HCC, 26 cases of ICC, 23 cases of liver cirrhosis, and 11 cases of normal liver tissues. The differences in the positive expression rate and strong positive expression rate of FSCN1 among different groups were analyzed. The positive rate of FSCN1 in normal liver tissues, liver cirrhosis, HCC, and ICC tissues was 0.0% (0/11), 0.0% (0/23), 13.9% (15/108), and 92.3% (24/26), respectively, while the strong positive rate was 0.0% (0/11), 0.0% (0/23), 0.9% (1/108), and 69.2% (18/26), respectively. Both the positive rate and strong positive rate of FSCN1 in ICC tissues were significantly higher than those in HCC, liver cirrhosis, and normal liver tissues. Additionally, the positive rate of FSCN1 in moderately to poorly differentiated HCC tissues was 18.8% (15/80), significantly higher than in well-differentiated HCC (0.0%, 0/28) (P = 0.031). In liver cancer, the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of FSCN1 positive prediction for ICC were 92.3%, 86.1%, 61.5%, and 97.9%, respectively, whereas the sensitivity, specificity, PPV, and NPV of FSCN1 strong positive prediction for ICC were 69.2%, 99.1%, 94.7%, and 93.0%, respectively. These results suggest that FSCN1 may play an important role in the occurrence and progression of liver cancer, and it can be used as a novel diagnostic marker for ICC.