Detection of human papillomavirus in plantar warts and its impact on outcome.

Cutaneous warts are caused by human papillomavirus (HPV) infection. Distinguishing plantar warts from clavus and tylosis can be difficult. A less-invasive method of examining these lesions is necessary. Previously, we collected data on 90 patients with warts and related diseases to explore differentiation methods using HPV typing of tissue from the wart surface. In that study, 21 patients were diagnosed as cases with plantar warts, however, 10 of those 21 cases showed HPV-negative by polymerase chain reaction analysis, causing some ambiguity, thus their outcomes should be confirmed. To assess the role of HPV typing in clinical practice, we followed up these 21 cases (11 HPV-positive and 10 HPV-negative) and analyzed their outcomes. The HPV-positive group included HPV1a (one case), HPV27 (four cases), HPV57 (three cases), and HPV65 (three cases). The median age of the 21 patients was 43 years, that of the 11 HPV-positive cases was 37 years, and that of the 10 HPV-negative cases was 44 years. The sex ratios (male:female) of the HPV-positive and HPV-negative groups were 6:5 and 2:8, respectively. All 21 patients were treated with liquid nitrogen after surface keratin removal, concomitant with salicylic acid topical plaster or oral administration of Yokuinin. The longest follow-up period was 548 days. Kaplan-Meier analysis was performed to assess the healing rate according to HPV-positivity. The healing rate in HPV-positive cases was significantly higher than in HPV-negative cases (P = 0.001). Although the sample size was small, the results suggest HPV typing using non-invasive surface materials facilitates accurate diagnosis and prevents prolonged treatment of plantar warts.

Antifibrotic effect of disulfiram on bleomycin-induced lung fibrosis in mice and its impact on macrophage infiltration.

The accumulation of monocyte-derived macrophages in the lung tissue during inflammation is important for the pathogenesis of fibrotic lung disease. Deficiencies in chemokine receptors CCR2 and CCR5 and their ligands, which mediate monocyte/macrophage migration, ameliorate bleomycin (BLM)-induced lung fibrosis. Disulfiram (DSF), which is used to treat alcoholism because of its aldehyde dehydrogenase (ALDH)-inhibiting effect, inhibits monocyte/macrophage migration by inhibiting FROUNT, an intracellular regulator of CCR2/CCR5 signalling. Here, we investigated the antifibrotic effect of oral DSF administration in a mouse model of BLM-induced lung fibrosis, focusing on macrophage response and fibrosis progression. The direct inhibitory activity of DSF on monocyte migration was measured using the Boyden chamber assay and compared with that of DSF-related inhibitors with different FROUNT-inhibition activities. Quantitative PCR was used to determine the expression of fibrosis-promoting genes in the lung tissue. DSF significantly suppressed macrophage infiltration into lung tissues and attenuated BLM-induced lung fibrosis. DSF and its metabolites, diethyldithiocarbamate (DDC) and copper diethyldithiocarbamate (Cu(DDC)2), inhibited monocyte migration toward the culture supernatant of primary mouse lung cells mainly comprising CCL2, whereas cyanamide, another ALDH inhibitor, did not. DSF, with higher inhibitory activity against FROUNT than DDC and Cu(DDC)2, inhibited monocyte migration most strongly. In BLM-induced fibrotic lung tissues, profibrotic factors were highly expressed but were reduced by DSF treatment. These results suggest DSF inhibits macrophage infiltration, which might be attributed to its inhibitory effect on FROUNT, and attenuates BLM-induced lung fibrosis. In addition, multiplex immunofluorescence imaging revealed reduced infiltration of S100A4+ macrophages into the lungs in DSF-treated mice and high expression of FROUNT in S100A4+ macrophages in idiopathic pulmonary fibrosis (IPF). These findings underscore the potential of macrophage-targeted therapy with DSF as a promising drug repositioning approach for treating fibrotic lung diseases, including IPF.

Case of tinea corporis caused by a terbinafine-sensitive Trichophyton indotineae strain in a Vietnamese worker in Japan.

A 42-year-old Vietnamese egg factory worker in Ishikawa prefecture, Japan, presented with itchy concentric erythema on the trunk and left calf. The lesions tested positive by direct potassium hydroxide examination, and two fungal strains were isolated. The isolates produced conidia abundantly and were morphologically indistinguishable from Trichophyton mentagrophytes/interdigitale, but were identified as Trichophyton indotineae by internal transcribed spacer sequence of ribosomal DNA. The lesions were refractory to treatment with topical luliconazole (LLCZ) cream for 4 weeks but subsided with oral itraconazole (ITCZ) 100 mg/day for 4 weeks in combination with topical lanoconazole (LCZ) cream. The lesions recurred 6 weeks after discontinuation of oral ITCZ, and an additional isolate was cultured. The minimum inhibitory concentrations of antimycotics for the isolate cultured at the first visit were: terbinafine (TBF) 0.03 µg/mL, ITCZ 0.015 µg/mL, LLCZ 0.0005 µg/mL, and LCZ 0.002 µg/mL. No TBF-resistant mutation in the amino acid sequence of squalene epoxidase, i.e., Leu 393 Ser/Phe or Phe 397 Leu, was detected in the isolate. The reason for recalcitrance in this case, despite the isolate's sensitivity to antimycotics, was unclear. Possible factors include insufficient use of the antimycotics, incomplete removal of abundantly produced conidia from the lesions, the patient's environment, and a language gap between the patient and physician hindering communication.

Renal Impairment of Proximal Tubular Injury Caused by Red Yeast Rice Supplement: Report of 2 Cases.

Introduction: Drug-induced tubulointerstitial injury is a common cause of renal impairment. Since the mechanisms of drug-induced tubular injury are diverse, various treatment approaches are needed according to the pathogenesis. Renal biopsy is indispensable to determine not only the pathological diagnosis, but also the underlying mechanism, and to guide appropriate treatment. Most recently, one of the red yeast supplements has been widely highlighted as a novel cause of tubular damage, mainly in Japan and Asia. However, neither detailed pathological findings nor the mechanism of renal impairment has been sufficiently reported. Case Presentation: Two cases of renal impairment after taking red yeast supplement internally are presented. Both cases showed renal dysfunction with low uric acid, potassium, and phosphorus levels, characteristic features of Fanconi syndrome. The renal biopsy findings of both cases showed severe injury to the proximal tubules with mild inflammatory cell infiltration. The proximal tubules exhibited diffuse loss of the brush border, flattening, and tubular lumen dilation. Immunofluorescence showed no deposition of immunoglobulin and complement in the glomeruli and tubules. Electron microscopic findings indicated proximal tubular damage without crystal deposition. Moreover, immunohistochemistry using the proximal tubular marker CD10 and a marker for distal tubules including the loop of Henle, E-cadherin, collectively demonstrated that the focus of renal injury in both cases was mainly the proximal tubules. Conclusions: The red yeast rice supplement itself, its metabolized product, or other unknown contaminant components might directly induce proximal tubulopathy rather than an allergic reaction-related tubulointerstitial nephritis.

Myeloperoxidase-Associated Membranous Nephropathy in Antineutrophil Cytoplasmic Antibody-Associated Glomerulonephritis.

Introduction: Antineutrophil cytoplasmic antibody (ANCA)-associated glomerulonephritis (GN) is characterized by pauci-immune crescentic GN. Myeloperoxidase ANCA-associated GN (MPO-ANCA GN) with membranous nephropathy (MN), where bright granular capillary MPO and IgG staining along the glomerular basement membrane (GBM) is present, has been reported; however, its clinicopathological features remain unclear. Methods: We investigated 7 MPO-ANCA GN with MN and 11 control cases (6 MPO-ANCA GN and 5 primary MN cases). Proteomics of laser microdissected glomeruli followed by immunohistochemical analysis was performed to identify causal antigens in MPO-ANCA GN with MN. We described the clinicopathological features of MPO-associated MN compared with those of MPO-ANCA GN and primary MN. Results: We detected proteomic MPO and granular capillary MPO deposits in all MPO-ANCA GN with MN cases. Confocal microscopy revealed MPO and IgG colocalization along the GBM. MPO-associated MN clinicopathological features include greater proteinuria, a higher fibrous crescent rate, and a lower MPO-ANCA titer than MPO-ANCA GN. The estimated glomerular filtration rate (eGFR) and urinary protein excretion were lower in MPO-associated MN than in primary MN. Conclusion: MPO-associated MN, a unique type of secondary MN where MPO serves as the causal antigen, is a subset of MPO-ANCA GN with MN. Prolonged periods of MPO-ANCA GN and a low MPO-ANCA titer might be related to MPO-associated MN development.

The clinicopathological and prognostic significance of autonomic nerves in salivary duct carcinoma.

Many researchers have focused on the role of the autonomic nervous system in the tumor microenvironment. Autonomic nerves include the sympathetic and parasympathetic nerves, which are known to induce cancer growth and metastasis. However, in salivary duct carcinoma (SDC), a rare and highly malignant tumor, the issue should be investigated from both biological and therapeutic perspectives. We explored the clinicopathological and prognostic implications of the autonomic nerves in 129 SDCs. Immunohistochemistry was performed to determine the nature of each nerve using antibodies against S100, tyrosine hydroxylase (TH) as a sympathetic marker, and vesicular acetylcholine transporter (VAChT) as a parasympathetic marker. The area of each marker-positive nerve was digitized and evaluated quantitatively. Double immunofluorescence for TH and VAChT was performed in selected cases. The expression of the secreted neurotrophins was also examined. S100-positive nerves were present in the cancer tissue in 94 of 129 cases (72.9%). Among them, TH-positive sympathetic nerves and/or VAChT-positive parasympathetic nerves were identified in 92 cases (97.9%), and 59 cases (62.8%) had TH/VAChT-co-expressing nerves. Double immunofluorescence revealed a mosaic pattern of sympathetic and parasympathetic fibers in co-expressing nerve bundles. The presence of autonomic nerves, regardless of their area, was significantly associated with aggressive histological features, advanced T/N classification, and a poor prognosis, with shorter disease-free and overall survival. There was an association between some tumor immune microenvironment-related markers and the autonomic nerve status, but not the latter and the secreted neurotrophin expression. This study suggests that autonomic nerves might play a role in the progression of SDC.

Predictability of combining Technetium-99m-galactosyl human serum albumin single-photon emission computed tomography/computed tomography and indocyanine green clearance test for posthepatectomy liver failure.

PURPOSE: To evaluate the predictive ability of combining Technetium-99m-galactosyl human serum albumin (99mTc­GSA) single-photon emission computed tomography (SPECT)/computed tomography (CT) volume and plasma clearance rate of indocyanine green (ICGK) for posthepatectomy liver failure (PHLF). MATERIALS AND METHODS: Fifty patients who underwent 99mTc-GSA scintigraphy as a preoperative examination for segmentectomy or more from July 2021 to June 2023 were evaluated prospectively. Patients were divided into two groups according to the presence or absence of posthepatectomy liver failure (PHLF). Total functional liver volume (t-FLV) and remnant FLV (r-FLV) were measured from 99mTc-GSA SPECT/CT image. Future liver remnant ICGK (ICGK-F) was calculated by ICGK and remnant liver volume from CT. Area under the curve (AUC) of ICGK-F, r-FLV, r-FLV/t-FLV, ICGK × r-FLV, ICGK × r-FLV/t-FLV was calculated to evaluate predictive ability of each parameter for PHLF. RESULTS: PHLF was occurred in 7 patients. AUC of ICGK × r-FLV was significantly higher than that of ICGK-F (0.99; 95% confidence interval [CI]: 0.96-1 vs 0.82; 95%CI: 0.64-0.96; p = 0.036). There was no significant difference between the AUC of r-FLV, r-FLV/t-FLV, ICGK × r-FLV/t-FLV and that of ICGK-F, respectively. CONCLUSION: The combination of 99mTc­GSA SPECT/CT volume and ICGK can predict PHLF more accurately than ICGK-F.

Impact of anatomical liver resection for hepatocellular carcinoma in preventing early-phase local recurrence after surgery.

BACKGROUND: The superiority of anatomical liver resection (AR) for localized hepatocellular carcinoma (HCC) over nonanatomical liver resection (NR) remains controversial. This study aimed to investigate the impact of AR in preventing local and early HCC recurrence. METHODS: A total of 280 patients who underwent initial liver resection for solitary HCC ≤5 cm in diameter were categorized into the AR and NR groups and compared using propensity score matching analysis. RESULTS: Between the matched pairs (n = 87 in each group), the incidence rates of local and early (recurrence within 2 years after surgery) recurrences in the AR group were significantly lower than those in the NR group (13.8% vs. 28.7%, p = .025; 20.7% vs. 35.6%, p = .028, respectively). The overall survival in the AR group was better than that in the NR group (median: 13.4 vs. 7.6 years, p = .003). NR was among independent risk factors for early recurrence (odds ratio: 1.98, 95% CI: 1.1-3.6, p = .023) and prognostic factors for local recurrence (hazard ratio: 2.44, 95% CI: 1.4-4.4, p = .003). CONCLUSION: AR is superior in controlling local and early recurrence postoperatively for solitary HCC ≤5 cm in diameter compared with NR.

Impact of Liver Fibrosis Severity on Oncological Prognosis in Hepatocellular Carcinoma.

Introduction: Cirrhosis is deemed to be a contributing factor to the postoperative recurrence of hepatocellular carcinoma (HCC); however, the precise impact of liver fibrosis on both cancer-specific prognoses remains unclear. This investigation sought to elucidate the effect of liver fibrosis severity on the cancer-specific prognosis. Methods: A total of 524 consecutive patients were included. Recurrence-free survival (RFS) and disease-specific survival (DSS) were compared according to fibrosis stage. Moreover, postoperative outcomes were subjected to analysis in cohorts of patients with F0 and F1-3, as well as in those with F1-3 and F4, who were carefully matched for background factors. Results: The 5-year RFS exhibited a significantly worse outcome in the F4 group compared to other stages of fibrosis: 5-year RFS - F0 (46.6%), F1-3 (33.1%), and F4 (23.5%), p = 0.03 (F0 vs. F1-3) and p < 0.01 (F1-3 vs. F4). Additionally, the 5-year DSS also presented a significantly worse prognosis in the F4 group: 5-year DSS - F0 (82.9%), F1-3 (73.6%), and F4 (57.4%), p = 0.04 (F0 vs. F1-3) and p < 0.01 (F1-3 vs. F4). In multivariate analysis, fibrosis 1, 2, 3, and 4 stage (compared with F0) (HR: 1.70, 1.81, 1.89, and 3.99, 95% confidence interval: 1.10-1.99, 1.39-2.22, 1.41-2.55, and 2.25-5.01, p = 0.022, p = 0.008, p < 0.001, and p < 0.001, respectively) was independent risk factor for RFS. After matched analysis, both RFS and DSS exhibited significantly worse prognoses in the presence of more advanced fibrosis. There was a significantly higher incidence of multiple recurrences in the F4 group than the F1-3 group, and a number of recurrences were observed both in the same hepatic segment as the resected side and in the contralateral lobe in F4 group. Discussion/Conclusion: The hazard and recurrence pattern of HCC signifies that the prognosis could potentially be poor, as the hepatic fibrosis likely owing to a higher hepatocarcinogenic potential, even in the absence of progression to cirrhotic condition. The risk of de novo recurrence may also increase with the progression of this fibrosis.

Surface material analysis for human papillomavirus detection in nail Bowen's disease caused by HPV type 58.

Over the past few years, cases of human papillomavirus (HPV) infection in nail Bowen's disease have been reported. This disease presents diagnostic challenges due to its similarity to nail malignant melanoma, particularly with respect to the clinical manifestation of black nail streaks. While skin biopsy is usually employed for diagnosis, it is an invasive procedure. We report the case of a 52-year-old healthy Japanese male with a pigmented streak on the nail of the fourth finger of his right hand, which had extended from the central to the lateral nail fold within 4 months. Dermoscopic examination revealed a dark-brown pigmented band with splinter microhemorrhage. Clinically, nail Bowen's disease was suspected. The lesion was excised in strips under local anesthesia. Histopathological examination revealed hyperkeratosis, parakeratosis, papillomatosis, and dyskeratotic cells with atypical nuclei irregularly arranged. Immunohistochemistry using anti-HPV L1 antibody detected HPV-positive cells in the upper epidermis and stratum corneum of the nail matrix. Mucosal high-risk HPV type 58 DNA was detected from brush cytology of the keratotic surface prior to surgery, which was confirmed in formalin-fixed, paraffin-embedded excised samples using polymerase chain reaction (PCR) and subsequent direct DNA sequencing. Our case highlights HPV type 58 as a potential causative agent of nail Bowen's disease and shows that brush cytology of the surface material prior to excision may be a useful and less invasive way for mucosal high-risk HPV detection. PCR analysis of the nail surface could serve as a supplementary diagnostic tool for nail Bowen's disease.

Trimebutine prevents corneal inflammation in a rat alkali burn model.

Alkaline burns to the cornea lead to loss of corneal transparency, which is essential for normal vision. We used a rat corneal alkaline burn model to investigate the effect of ophthalmic trimebutine solution on healing wounds caused by alkaline burns. Trimebutine, an inhibitor of the high-mobility group box 1-receptor for advanced glycation end products, when topically applied to the burned cornea, suppressed macrophage infiltration in the early phase and neutrophil infiltration in the late phase at the wound site. It also inhibited neovascularization and myofibroblast development in the late phase. Furthermore, trimebutine effectively inhibited interleukin-1ß expression in the injured cornea. It reduced scar formation by decreasing the expression of type III collagen. These findings suggest that trimebutine may represent a novel therapeutic strategy for corneal wounds, not only through its anti-inflammatory effects but also by preventing neovascularization.

Maxillary Sinus NUT Carcinoma: A Case Report.

Background/Aim: Nuclear protein in testis (NUT) carcinoma is extremely rare, occurs in the midline of the body, progresses rapidly and is refractory to treatment; most patients die within a year. Here, we describe a case of maxillary sinus NUT carcinoma presenting with epistaxis and nasal obstruction that was treated as a standard head and neck carcinoma. Case Report: The patient was a 41-year-old male with a left buccal swelling; the diagnosis was made of primary NUT carcinoma of the left maxillary sinus and bone metastasis in the cervical spine. After induction chemotherapy with docetaxel plus cisplatin and 5-fluorouracil, the tumor decreased in size, and the patient was further treated with cisplatin and radiation therapy. One month after that, the tumor remained small, however, lung metastasis was observed. Therefore, nivolumab was administered. Cetuximab and paclitaxel were administered after the lung metastasis worsened, but the patient developed progressive disease and died 11 months after diagnosis. Conclusion: Effective treatments for NUT carcinoma have not yet been established. However, early testing to establish the diagnosis may provide useful insights to guide clinical decisions to improve patient outcomes.

Parotid Gland Cancer With First Bite Syndrome Detected via CT-Guided Fine Needle Aspiration Cytology.

BACKGROUND/AIM: First bite syndrome (FBS) is a symptom of severe pain at the beginning of a meal that lessens as the meal progresses. It is a common postoperative complication of parapharyngeal space tumors and is rarely reported as the first symptom of parotid carcinoma. The parapharyngeal space is considered a difficult area for approach; hence, preoperative histopathology is often challenging. However, there are hardly any reports on the approach of performing biopsies under computerized tomography (CT) guidance. CASE REPORT: A 28-year-old woman presented to our hospital with the chief complaint of pain in the left parotid region since the past year. Contrast-enhanced magnetic resonance imaging of the parotid gland revealed a 10-mm high-signal area on T2-weighted images extending from the deep lobe of the left parotid gland to the parapharyngeal space, which could not be visualized on ultrasound. She was suspected to have a malignant tumor because of the presence of a parotid tumor with FBS. Therefore, she underwent CT-guided fine-needle aspiration cytology (FNAC) and was diagnosed with adenoid cystic carcinoma. The patient underwent left parotid tumor resection and left cervical dissection, and her pain during feeding improved postoperatively. CONCLUSION: In a patient with parotid tumor extending into the parapharyngeal space with FBS as the initial symptom, CT-guided FNAC was successfully used to diagnose parotid carcinoma. Symptoms of pain, including FBS, should be considered in cases of malignancy. CT-guided FNAC is effective for lesions that cannot be visualized by ultrasound, such as those in the parapharyngeal space.

Long-term remnant liver volume dynamics after major hepatectomy for perihilar cholangiocarcinoma following portal vein embolization.

BACKGROUND: Portal vein embolization (PVE) followed by major hepatectomy is a common treatment strategy for patients with perihilar cholangiocarcinoma (PHCC); however, the long-term dynamics of the liver remnant volume (LRV) remain unclear. Here, we report the dynamics of the LRV in patients who underwent hepatectomy following PVE. METHODS: A total of 39 patients with PHCC who underwent right hemihepatectomy or left trisectionectomy with extrahepatic bile duct resection between 2004 and 2021 were enrolled in this study [PVE (n = 27) and non-PVE (n = 12]). Long-term remnant liver dynamics were analyzed in propensity score-matched pairs (n = 10/group). RESULTS: The LRV/future liver remnant volume (FLRV) at 1 week to 1 month after hepatectomy were smaller in the PVE group than in the non-PVE group (1.53 vs. 1.69, p = .044 and 1.52 vs 1.99, p = .003, respectively). In the non-PVE group, the LRV/FLRV ratio plateaued 1-3 months postoperatively, whereas progressive hypertrophy occurred in the PVE group, and the LRV/FLRV ratio became equal in both groups at 1 year after hepatectomy (1.96 vs. 1.97; p = .799). Multivariate analysis revealed that FLRV/total liver volume (TLV) ≤ 0.43 was the only independent predictor of LRV/FLRV ≥1.9 at 1 year after hepatectomy (odds ratio:5.345, 95% confidence interval:1.210-23.615; p = .027). CONCLUSION: Although the long-term LRV was nearly equal in both groups, short-term LRV hypertrophy was lower in the PVE group than in the non-PVE group.

Disulfiram treatment suppresses antibody-producing reactions by inhibiting macrophage activation and B cell pyrimidine metabolism.

Antibody responses, involving B cells, CD4 + T cells, and macrophages, are implicated in autoimmune diseases and organ transplant rejection. We have previously shown that inhibiting FROUNT with disulfiram (DSF) suppresses macrophage activation and migration, effectively treating inflammatory diseases. In this study, we investigated the effectiveness of DSF in antibody-producing reactions. Using a heart transplantation mouse model with antibody-mediated rejection, we administered anti-CD8 antibody to exclude cellular rejection. DSF directly inhibited B cell responses in vitro and significantly reduced plasma donor-specific antibodies and graft antibody deposition in vivo, resulting in prolonged survival of the heart graft. DSF also mediated various effects, including decreased macrophage infiltration and increased Foxp3+ regulatory T-cells in the grafts. Additionally, DSF inhibited pyrimidine metabolism-related gene expression induced by B-cell stimulation. These findings demonstrate that DSF modulates antibody production in the immune response complexity by regulating B-cell and macrophage responses.

Consistent survival in consecutive cases of life-supporting porcine kidney xenotransplantation using 10GE source pigs.

Xenotransplantation represents a possible solution to the organ shortage crisis and is an imminent clinical reality with long-term xenograft survival in pig-to-nonhuman primate (NHP) heart and kidney large animal models, and short-term success in recent human decedent and clinical studies. However, concerns remain about safe clinical translation of these results, given the inconsistency in published survival as well as key differences between preclinical procurement and immunosuppression and clinical standards-of-care. Notably, no studies of solid organ pig-to-NHP transplantation have achieved xenograft survival longer than one month without CD40/CD154 costimulatory blockade, which is not currently an FDA-approved immunosuppression strategy. We now present consistent survival in consecutive cases of pig-to-NHP kidney xenotransplantation, including long-term survival after >3 hours of xenograft cold preservation time as well as long-term survival using FDA-approved immunosuppression. These data provide critical supporting evidence for the safety and feasibility of clinical kidney xenotransplantation. Moreover, long-term survival without CD40/CD154 costimulatory blockade may provide important insights for immunosuppression regimens to be considered for first-in-human clinical trials.

An Immunohistochemical Analysis of Osteopontin and S100 Calcium-binding Protein P is Useful for Subclassifying Large- and Small-duct Type Intrahepatic Cholangiocarcinomas.

Intrahepatic cholangiocarcinoma (iCCA) has been newly subclassified into two different subtypes: large-duct (LD) type and small-duct (SD) type. However, many cases are difficult to subclassify, and there is no consensus regarding subclassification criteria. LD type expresses the highly sensitive diagnostic marker S100 calcium-binding protein P (S100P), while SD type lacks sensitive markers. We identified osteopontin (OPN) as a highly sensitive marker for SD type. This study aimed to develop new subclassification criteria for LD-type and SD-type iCCA. We retrospectively investigated 74 patients with iCCA and subclassified them based on whole-section immunostaining of S100P and OPN. Of the 74 cases, 41 were subclassified as LD type, 32 as SD type, and one was indeterminate. Notably, all S100P-negative cases had OPN positivity. Seventy-three of the 74 cases (98.6%) were clearly and easily subclassified as LD or SD type using only these 2 markers. We also determined the value of immunohistochemistry in cases that were difficult to diagnose based on hematoxylin-eosin and Alcian blue-periodic acid-Schiff staining. Furthermore, we analyzed the clinicopathological characteristics and prognoses of these 2 subtypes. LD type was a poor prognostic factor on univariate analysis; it had significantly worse overall survival ( P = 0.007) and recurrence-free survival ( P < 0.001) than the SD type. In conclusion, we propose new subclassification criteria for iCCA based on immunostaining of S100P and OPN. These criteria may help pathologists to diagnose subtypes of iCCA, supporting future clinical trials and the development of medications for these 2 subtypes as distinct cancers.