Comparison of Cajal-like cells in pelvis and proximal ureter of kidney with and without hydronephrosis.

OBJECTIVES: To evaluate effects of Cajal-like cells on human renal pelvis and proximal ureter on peristalsis. MATERIALS AND METHODS: 63 patients submitted to nephrectomy due to atrophic non-functional kidney associated with hydroureteronephrosis were included as study group and 30 cases with nephrectomy due to other reasons were included as control group. Samples from renal pelvis and proximal ureters were obtained and sections of 5µ form paraffin blocks of these samples were prepared; layers of lamina propria and muscularis mucosa were examined by immune-histochemistry using CD117 in order to determine count and distribution of Cajal-like cells. RESULTS: During immune-histochemical examinations of sections, obtained from renal pelvis and proximal ureter of hydronephrotic kidneys by CD117, Cajal-like cells number determined in lamina propria and muscularis propria was statistically significantly lower compared to control group (p<0.001). Distribution of Cajal-like cells in renal pelvis and proximal tubulus was similar under examination by light microscope, and also both groups were not different from each other regarding staining intensity of Cajal-like cells by c-kit. CONCLUSION: Significantly reduced number of Cajal-like cells in study group compared to control group, shows that these cells may have a key role in regulation of peristalsis at level of renal pelvis and proximal ureter in urinary system.

Evaluation of malignant and benign renal lesions using diffusion-weighted MRI with multiple b values.

BACKGROUND: Limited data are available regarding the use of diffusion-weighted (DW) magnetic resonance imaging (MRI) with multiple b values for characterization of renal lesions. PURPOSE: To demonstrate and compare the diagnostic performance of DW-MRI with multiple b values for renal lesion characterization. MATERIAL AND METHODS: Sixty-three lesions (36 malignant, 27 benign) in 60 consecutive patients (48 men, 12 women; age 60 ± 12.5 years) with solid/cystic renal lesion diagnosed after MRI were included prospectively. Single-shot echo-planar DW abdominal MRI (1.5T) was obtained using seven b values with eight apparent diffusion coefficient (ADC) maps. Contrast-to-noise ratios (CNRs), signal intensities, lesion ADCs, and lesion/normal parenchyma ADC ratios were analyzed. Receiver-operating characteristic analysis was performed. RESULTS: The mean signal intensities of malignant lesions (at b0, 50, and 200s/mm(2)) were significantly lower than those of benign lesions (P < 0.05). The mean ADC values at all b value combinations of malignant lesions were significantly lower than those of benign lesions (P < 0.000), excluding the ADC value at b50 s/mm(2). ADC with all b values could better distinguish between benign and malignant lesions. A 1.35 × 10(-3) mm(2)/s threshold ADC value permitted this distinction with 85.2% sensitivity and 65.6% specificity. The lesion/normal parenchyma ADC ratio was more effective than the lesion ADC. CONCLUSION: In addition to the ADC value, the signal intensity curve on DW images using multiple b values could be helpful for differentiation of malignant and benign renal lesions.

Comparison of efficacy of Oral versus Intra-articular Corticosteroid Application in the treatment of Frozen Shoulder: An experimental study in rats.

OBJECTIVE: The aim of this study was to compare clinical and histopathological effects of oral versus intraarticular corticosteroid application in a rat model of frozen shoulder. METHODS: In this study, eighty adult Sprague-Dawley rats were used. The animals were divided into 5 equal groups. The frozen shoulder model was created by immobilizing animals' shoulders with internal fixation with sutures for 8 weeks. At the 8th week, sham (n: 16) and control (n: 16) groups were sacrificed to collect data for healthy and affected shoulders. Also, at the 8th week, 50 mg/ kg methylprednisolone was started for the oral treatment group, and a single dose of 0.5 mg/kg triamcinolone acetonide was injected for the intraarticular treatment group. The effect of additional steroid treatment was expected for 2 weeks, then all remaining treatment and natural course groups were sacrificed on the 10th week. RESULTS: After sacrification, specimens taken as "en bloc" scapulothoracic disarticulation were randomly divided into two groups for a range of motion measurement and histopathological examination. The control (frozen shoulder model) group's shoulder range of motion in all directions was lower than the sham (healthy) group (P < 0.01). Natural course and intraarticular steroid groups, compared to the frozen shoulder model showed a significant increase in the direction of abduction (P < 0.05). Also, it was found for treatment groups that in all directions the range of motion was not as good as the healthy values (P < 0.01). The intraarticular treatment group showed higher degrees of abduction compared to the natural course and oral steroid treatment groups (P < 0.01). Oral steroid treatment group's range of motion was not significantly better than the disease model and had no superiority to the natural course group (P > 0.05). Histopathologically, no statistically significant difference was observed between the groups for signs of frozen shoulder which was found in the immobilized group (P > 0.05). Histopathologically, immobilization was found to cause thickening of the capsule that cannot be resolved by treatment. (P < 0.05). CONCLUSION: In frozen shoulder disease, intraarticular steroid injection seems to be superior in increasing the range of motion than oral steroid treatment.

Clinicopathologic characteristics and surgical management of schwannomas of the upper digestive tract.

AIM: Schwannoma is a peripheral nervous system tumor arising from Schwann cells of the neural sheath, and they are very rarely seen in the upper digestive tract. In this study, we aimed to present the clinicopathologic characteristics and surgical management of patients who underwent surgical treatment for esophageal or gastric schwannoma. MATERIAL AND METHODS: Patients who were diagnosed with esophageal or gastric schwannoma between January 2013 and January 2020 were included in the study. Demographic, clinicopathological and immunohistochemical parameters of the patients were analyzed along with the follow-up results. RESULTS: There were 13 patients in our study. Nine patients had gastric schwannoma and 4 patients had esophageal schwannoma. Female gender was dominant (61.5%). The mean age was 56 years. Esophageal tumors were all enucleated. Minimal invasive approach was preferred in 3 patients. Gastric tumors were most commonly localized in the lesser curvature. Three patients underwent laparoscopic wedge resection, 3 patients open wedge resection, 2 patients subtotal gastrectomy, and one patient proximal gastrectomy. Intraoperative or postoperative complications did not develop in any patient. No patient required reoperation, and there were no deaths within 90 days postoperatively. In the postoperative 90-day period, there was no unplanned re-admission to the hospital. The mean follow-up period was 53.4 months (range: 23-93 months). No recurrence was detected in any patients. CONCLUSIONS: Definitive diagnosis of schwannomas is made only by histopathologic examination postoperatively. S-100 expression has diagnostic significance. The preferred treatment is complete surgical excision with negative margins, and the long-term outcome is excellent as these lesions are mostly benign. KEY WORDS: Esophagus, Enucleation, Schwannoma, Stomach, Wedge resection.

Germline DICER1 mutations and familial cystic nephroma.

BACKGROUND: Multilocular cystic nephroma (CN) is a benign kidney tumour and is part of a family of kidney neoplasms including cystic partially differentiated nephroblastoma and Wilms tumour (WT). CN is rarely familial or bilateral, but it occurs in about 10% of families where pleuropulmonary blastoma (PPB) is present. Recently, germline mutations in DICER1 were found in familial PPB. OBJECTIVE: To search for DICER1 mutations in two families with familial CN; PPB was present in one family. Additionally, to test germline DNA from 50 children with sporadic WT for DICER1 mutations. RESULTS: Both families with multiple CN were found to have mutations in DICER1 leading to premature stop codons, predicted to result in loss of the ribonuclease and dsRNA binding domains. These domains are essential to the function of DICER1. No germline mutations were found in any of the 50 children who had developed WT. CONCLUSION: It has been established that DICER1 mutations cause familial CN and may be implicated in bilateral CN. No germline mutations were found in the patients with WT, suggesting that DICER1 mutations are unlikely to have a major role in the aetiology of sporadic WT. These results provide further evidence implicating miRNA dysregulation in tumourigenesis.

Nitric oxide in gingival crevicular fluid and nitric oxide synthase expression in the gingiva of patients with sickle cell disease.

OBJECTIVE: This study aimed to biochemically measure the production of nitric oxide in gingival crevicular fluid and immunohistochemically measure the expression of inducible nitric oxide synthase in the gingiva of patients with sickle cell disease. Additionally, we aimed to obtain insight into the immunopathology of sickle cell disease by comparing inducible nitric oxide synthase levels in patients with sickle cell disease and controls using gingiva and gingival crevicular fluid. METHODS: The study included 20 sickle cell disease patients and 20 healthy controls. Immunohistochemical analysis was used to measure inducible nitric oxide synthase expression in gingiva and nitric oxide levels in gingival crevicular fluid were spectrophotometrically measured. RESULTS: Nitric oxide levels in the patients and controls did not differ significantly (21.2±4.5 and 23.1±2.3 µM L-1, respectively, p>0.05). There weren't any statistically significant differences in infiltrated inflammatory cells, density of inflammatory cells that stained with inducible nitric oxide synthase, or nitric oxide expression in gingiva between the patient and control groups (p>0.05). CONCLUSION: To the best of our knowledge this is the first study to examine the expression of inducible nitric oxide synthase in the gingiva and gingival crevicular fluid in patients with sickle cell disease. Using the gingiva and gingival crevicular fluid we were unable to observe sickle cell disease-associated inducible nitric oxide synthase expression and a difference in nitric oxide levels.

18F-FDG PET/CT Imaging in an Unusual Case of Cutaneous Melanoma Arising From Congenital Melanocytic Nevus in a Two-year-old Girl

Childhood malignant melanoma (MM) is extremely uncommon. We report an unusual case of cutaneous melanoma that developed from a medium-sized congenital melanocytic nevus (CMN) in a two-year-old girl. The patient had a history of CMN on the right hip, and she presented with a new ulcerative area with irregular borders and bleeding on CMN. Histopathological examination of the nevus revealed a MM. 18Florfluorodeoxyglucose (18F-FDG) positron emission tomography/computed tomography was performed for metastatic evaluation. The scan demonstrated metastatic increased 18F-FDG uptake in the right external iliac and inguinal lymph nodes.

Management of facial disfigurement in orbitotemporal neurofibromatosis.

A 19-year-old woman with type I neurofibromatosis requested reconstruction of her severe facial disfigurement caused by the plexiform neurofibroma of the right upper eyelid. Previously, she had glaucoma surgery for buphthalmus and enucleation with dermis fat transplantation. She was unable to wear prosthesis in the last year. Transverse palpebral resection of the lesion, lateral canthal reconstruction, and frontal sling ptosis surgery were performed at the same session. Postoperatively, the cosmetic appearance of the patient was markedly improved. No complication or progression was observed during 2 years follow-up. We believe that an individual-based surgical plan may give acceptable results in these challenging cases.

Nasolacrimal duct obstruction: clinicopathologic analysis of 205 cases.

PURPOSE: To investigate the histopathological results of lacrimal sac biopsies in patients with primary acquired nasolacrimal duct obstruction. METHODS: In this prospective non-comparative study, 205 consecutive patients, who were diagnosed as primary acquired nasolacrimal duct obstruction, were included. Patients with history of trauma and/ or surgery in the periorbital area, punctum or canalicular obstruction were excluded from the study. Patients were evaluated for age, gender, history, and presenting symptoms. Lacrimal drainage system abnormalities were assessed. Lacrimal system irrigation, dacryocystography, and in selected cases dacryoscintigraphy was performed. All patients underwent external dacryocystorhinostomy. Biopsy specimens were obtained from the posterior inferior flap and examined by the same pathologist. RESULTS: Forty-seven male and 158 females with age ranging from 6 to 81 years (mean 47.5 ± 16.2 years) were included in the study. Only one patient had the diagnosis of chronic leukemia, others had no preexisting history of systemic disease. Pathologic examination revealed chronic inflammation (n= 178), fibrosis without inflammation (n= 19), normal mucosa (n= 4), and lymphoid hyperplasia (n= 1). Three patients had abnormal pathology: Lymphoproliferative disease in the patient with chronic leukemia, granulomatous inflammation, and basosquamous cell carcinoma. CONCLUSION: In primary nasolacrimal duct obstruction, pathological examination of the lacrimal sac revealed chronic inflammatory changes in most patients. Even though rare, malignant or systemic disease in patients with neither specific history nor clinical or radiological finding might be observed in these cases. Thus, we recommend taking biopsy if any suspicion of abnormality of the lacrimal sac exists.

Effects of vas deferens obstruction on Cajal-like cells in rats.

OBJECTIVE: Cajal cells have been defined as pacemakers in the gastrointestinal tract, and have recently been reported in the urogenital tract. In this study, the effects of experimental obstruction of the vas deferens on Cajal-like cells in rats were investigated. MATERIAL AND METHODS: Ninety rats were divided into study (S), sham-operated (SH) and control (C) groups. The vasa deferentia were removed at the beginning of the study in the C group and in the 1st, 2nd and 3rd months after distal vas deferens ligation in the SH and S groups (S1, S2 and S3 consecutively). The sections stained with c-kit antibody were studied under a light microscope to determine the number and morphology of Cajal-like cells in the submucosal and muscular layers. RESULTS: There were no statistically significant differences between the C, S1 and S2 groups despite a higher mean in S1. The decrease in the mean values for the submucosal and muscular layers in S3 was statistically significant compared to the C group. No morphologically significant difference was detected under a light microscope after obstruction. CONCLUSIONS: The increase in Cajal-like cells in the early phase, although insignificant, might be associated with increased motility to overcome the obstruction, whereas the significant decrease in the late phase might be a sign of disordered motility.

p53 expression in pterygium in two climatic regions in Turkey.

PURPOSE: To assess accumulation of p53 protein in samples of primary pterygium from people living in two different climatic regions in Turkey. MATERIALS AND METHODS: Group 1 included 101 pterygium specimens from people in Adana located in southern Turkey. Group 2 included 39 pterygium specimens from people in Ankara, located in the middle of Turkey. Climatic conditions throughout the year are sunnier and warmer in Adana than they are in Ankara. The control group (Group 3) included 30 specimens of conjunctiva that had been excised during cataract surgery from 30 patients without pterygium. The pterygial specimens and control conjunctiva were studied by immunohistochemistry using antibodies against p53 protein. Pearson's chi-square test was used to compare the p53 immunoreactivity. RESULTS: The p53 immunoreactivity in Groups 1 and 2 was greater than it was in the control group ( P 0.001). There were no differences in p53 immunoreactivity between Groups 1 and 2 ( P= 0.060). CONCLUSION: The p53 immunoreactivity was not correlated with ultraviolet irradiation exposure. The p53 immunoreactivity in our pterygium specimens suggests that pterygium could be a result of uncontrolled cell proliferation.

Squamous cell carcinoma of the penis: a clinicopathological study from a population with late circumcision.

Squamous cell carcinoma (SCC) of the penis has been subject to only a few studies in populations where late childhood circumcision is performed. To asses clinicopathological features and human papillomavirus (HPV) status of penile SCC in men with late circumcision, eight institutions in the country volunteered to collaborate and 15 cases of penile SCC were collected from their pathology archives. The presence and genotype of HPV were determined in addition to clinicopathological features of the tumors. Findings were correlated with disease outcome. The mean age of the patients evaluated was 66.5 years. Histological subtypes were usual SCC (6∕15), papillary (2∕15), mixed (2∕15), basaloid (2∕15), acantholytic (1∕15), pseudohyperplastic (1∕15), and warty-basaloid (1∕15) carcinomas. HPV was identified in 33.3% of samples; HPV16 was detected in 60% of positive cases and was associated with basaloid and/or warty morphology. Cause-specific 1-year and 2-year survivals were 76.9% and 54.5%, respectively. The usual subtype and nodal metastasis were associated with worse outcome (p=0.045 and p=0.047, respectively). As a conclusion, our results suggest an inclination for penile SCC to develop at a later age in a population with late circumcision than the patients from the regions of high penile cancer incidence. These men seem to have less frequent HPV association and their outcome appears poorer than other populations, although reaching substantial provision is not possible due to our limited case number.

Maspin, E-selectin, and P-selectin expressions in papillary thyroid carcinomas and their correlation with prognostic parameters.

Maspin is a serine protease inhibitor belonging to the serpin family, and is known as a tumor-suppressor protein. Maspin also exhibits an inhibitor effect on angiogenesis. Cell adhesion molecules such as E- and P-selectin are known to play an important role in the metastasis mechanism. We evaluated the expression of maspin, E- and P-selectin in 74 papillary thyroid carcinomas, 19 of which had lymph node metastases, and statistically analyzed the relationship between these three proteins and their relation with prognostic factors. Positive correlations were found for maspin positivity and lymph node metastases; thyroid capsule invasion and perithyroidal soft tissue invasion; E-selectin positivity and lymph node metastases, lymphovascular invasion and perithyroidal soft tissue invasion; and P-selectin positivity and lymph node metastases and lymphovascular invasion (p < 0.05). Statistically significant correlations were also found between maspin, E- and P-selectin expressions with each other and with tumor stage (p < 0.05). Inactive cytoplasmic maspin cannot act as a tumor suppressor. Expression of E- and P-selectins in tumor cells facilitates the occurrence of metastases, lymphovascular invasion, and perithyroidal soft tissue invasion. Further studies, in particular molecular investigations, are needed to reveal the detailed interactions between maspin, E-selectin, and P-selectin expression.

Effects of different suture materials on cartilage reshaping.

OBJECTIVE: To examine the effects of different suture materials and suturation techniques on cartilage reshaping in a rabbit model. METHODS: Twenty-two rabbits were used. Posterior skin flaps were elevated, and 4 cartilage struts were prepared on each auricula. Each strut was bent at its midpoint, and the skin under the bent area was elevated only in 1 side. The strut was sutured either with catgut, polyglactin 910, polydioxanone, or polypropylene sutures. Anteriorly, the suture was passed subcutaneously on 1 side, while transcutaneously on the other. Animals were killed at the first and fourth months. The shape of the struts was macroscopically evaluated. Inflammation and foreign body reaction around the suture were examined under light microscopy. RESULTS: Maintenance of shape with all suture materials was significantly lower in the transcutaneously sutured group than in the subcutaneously sutured group. Because of high rates of suture loss in the transcutaneously sutured group, further evaluations on cartilage tissue were made only in subcutaneously sutured group. Success rate in maintenance of shape was similarly high in the polydioxanone, polyglactin 910, and polypropylene suture groups; however, it was significantly lower in the catgut suture group. CONCLUSION: Long-lasting absorbable suture materials are as effective as nonabsorbable ones, and the subcutaneous technique is more effective than the transcutaneous technique.

Malignant eccrine spiradenoma of the scalp.

Malignant eccrine spiradenoma is a rare neoplasm generally arising from long-standing benign eccrine spiradenomas; it is rarely seen on the scalp. A 27-year-old woman with a malignant eccrine spiradenoma of the scalp, which had occurred 8 months after the inadequate excision of a benign eccrine spiradenoma, was treated at our hospital. The patient underwent lymphoscintigraphy. A biopsy of the sentinel lymph nodes in the right periparotid and left occipital regions was performed, and the nodes showed no metastases. The tumor with its large subcutaneous extension and the outer table of the cranium were removed. A split-thickness skin graft was applied on the exposed inner table. At 24 months' follow-up, there has been no tumor recurrence. We report a case of a malignant eccrine spiradenoma of the scalp with cranial involvement that arose from an inadequately removed, long-standing, benign eccrine spiradenoma in a young patient. Also, we review the existing literature on malignant eccrine spiradenoma of the scalp.

Congenital intracranial teratoma with massive macrocephaly and skull rupture.

OBJECTIVE: Congenital intracranial tumors are rare and only account for 0.5-1.5% of all pediatric brain tumors. Teratoma is the most frequently encountered intracranial tumor at birth. Massive congenital intracranial teratoma is an extremely rare neoplasm with a poor prognosis. They grow rapidly and cause extensive destruction in the brain. Herein we report a massive intracranial teratoma causing skull rupture. CASE REPORT: A fetus with a congenital intracranial teratoma presenting with a disproportionately enlarged head at 25 weeks of gestation is presented. Since it was the first admission of the mother to a medical expert for a prenatal examination, there was noprevious follow-up data. Prenatal ultrasonography demonstrated a huge, heterogeneous intracranial mass, and midline structures and ventricles could not be observed. No heartbeat was detected. Autopsy was perforated, and histopathologic examination of the samples taken from the intracranial mass revealed an immature teratoma. CONCLUSION: Although congenital intracranial teratomas are rare, they may reach enormous sizes. Regular follow-up of the fetus may lead to early diagnosis of immature intracranial teratomas and prevent the mother from having further complications either due to intrauterine fetal death orpsychological trauma of giving birth to a heavily malformed baby.

Uncommon locations of hydatid cyst.

OBJECTIVE: To document the hydatid cyst cases in the endemic Cukurova region of Turkey, by their involvement sites in the body, and discuss the clinical and morphological features of the cases with rare localization. METHODS: Archival materials of 153 hydatid cyst cases that were diagnosed in 2 different medical centers in Adana, Turkey Cukurova region between the years 2000-2006 were included in the study. Cases with rare localizations were reevaluated in terms of clinical and laboratory findings, and histopathological features. Involvement sites of the cases were documented, and cases with rare localizations are discussed. RESULTS: The liver was the most common localization with 63 cases followed by lungs with 54 cases. Uncommon locations were spleen n=4, bone n=3, intraarterial n=1, ovary n=1, adrenal n=1, heart n=1, mesenteric n=2, retroperitoneal n=2, subcutaneous tissue n=4, breast n=3, intramuscular tissue n=4. CONCLUSION: The diagnosis of hydatic cyst should be considered in patients with a cystic mass, who live or have lived in a geographic region that has a high risk for Echinococcus granulosus, or visited an endemic area.

Mucinous cystadenoma of the appendix: a rare cause of acute abdomen.

BACKGROUND: We aimed to assess the acute abdominal conditions due to appendiceal mucinous cystadenomas. METHODS: We retrospectively evaluated 11 patients with histopathologically confirmed appendiceal mucinous cystadenoma. Patient charts and data on patient demographics; clinical features; ultrasonography (US), colonoscopy and computed tomography (CT) findings; pathology reports; and operative and postoperative management were reviewed. RESULTS: The incidence of appendiceal mucinous cystadenoma was 0.95% of all appendectomy specimens reviewed. In our review, there were 11 patients, five of whom were women. The median age was 70 years (50-85 years), and the most common presentation was abdominal pain (81.8%). On US in eight patients, findings were abdominal cystic mass and cyst wall calcification. The CT finding was well-encapsulated cystic mass in eight patients. In one case, a colonic mass was found in colonoscopic examinations. There was one patient with concomitant colon cancer. Appendectomy was performed in nine patients and right hemicolectomy was performed in two patients. CONCLUSION: Colonoscopy, US, and CT are useful tools in diagnosing mucocele and synchronous cancer. However, diagnosis is usually made intraoperatively or postoperatively on histopathological examination. Appendectomy is the standard of care for mucinous cystadenoma. Furthermore, it is important to prevent spillage of the mucocele content.

Comparison of the inhibitory effect of different doses of subconjunctival bevacizumab application in an experimental model of corneal neovascularization.

AIM: To evaluate the inhibitory effect of subconjunctival bevacizumab as single- and multiple-dose application, and compare their effects on corneal neovascularization in a rat model. METHODS: Thirty adult Sprague-Dawley rats were used in this experimental study. The central cornea of the rats was cauterized chemically. The rats were randomly enrolled into three groups. All groups received subconjunctival injections. In Group 1 (control group, n=10), 0.05 mL 0.9% NaCl solution was injected on the first day. In Group 2 (single-dose group, n=10), 0.05 mL bevacizumab (1.25 mg) was injected on the first day. In Group 3 (multiple-dose group, n=10), four doses of 0.05 mL bevacizumab (1.25 mg) were injected on the first, third, fifth and seventh day. Slit-lamp examination of all rats was performed at the third and ninth day. Digital images of the corneas were taken and analyzed using image analysis software to calculate corneal neovascularization area. All rats were sacrificed on the tenth day. In corneal sections, the number of blood vessels, state of inflammation and collagen formation was evaluated histopathologically. RESULTS: In Group 3, corneal edema grades were significantly lower than Group 1 and Group 2 (P=0.02, and P=0.035, respectively). The mean percentage of neovascularized corneal area in Group 3 was significantly lower than Group 2 (P=0.005). On histopathological examination, Group 2 and Group 3 showed significantly less number of blood vessels than Group 1 (P=0.005, and P=0.001, respectively). Additionally, Group 3 showed significantly less number of blood vessels compared to Group 2 (P=0.019). Inflammation and edema grades were significantly lower in Group 3 compared to Group 1 (P=0.001). CONCLUSION: Subconjunctival bevacizumab injection is effective in inhibition of newly formed corneal neovascularization. The multiple-dose bevacizumab treatment seems to be more effective compared to single-dose treatment.

Human Epidermal Growth Factor Receptor 2 Overexpression in Micropapillary and Other Variants of Urothelial Carcinoma.

BACKGROUND: Human epidermal growth factor receptor 2 (HER2) protein overexpression or gene amplification has been shown in urothelial bladder cancer. This could be helpful when using targeted anti-HER2 therapy on these tumors. OBJECTIVE: To evaluate HER2 immunohistochemical expression in conventional urothelial carcinoma (UC), in situ UC, and UC variants primarily in micropapillary urothelial carcinoma (MPUC). DESIGN, SETTING, AND PARTICIPANTS: The study evaluated 60 MPUC cases; 25 invasive, 20 low-grade noninvasive, and 10 high-grade noninvasive UC cases; 8 in situ UC cases; and 69 UC variant cases. The immunohistochemistry staining was scored according to recommendations of the American Society of Clinical Oncology/College of American Pathologists 2013 HER2 test guideline established for breast cancer and only 3+ staining was considered HER2 overexpression. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: HER2 overexpression was determined by 3+ staining. RESULTS AND LIMITATIONS: 34 of 60 MPUC cases (56%) showed HER2 overexpression (3+ staining). We observed 3+ staining HER2 overexpression in nine of 25 conventional invasive UC cases (36%), four of eight in situ UC cases (50%), and three of six lipid cell variant cases (50%). 3+ staining HER2 overexpression was not seen in eight glandular, six small cell, and five sarcomatoid variant cases. HER2 overexpression was negative in the 20 low-grade noninvasive UC cases but positive in two of the 10 high-grade noninvasive UC cases (20%). We observed HER2 overexpression most commonly in MPUC cases. We also found HER2 overexpression in conventional invasive and in situ UC cases. CONCLUSIONS: Pure in situ UC and conventional invasive UC, especially MPUC, could be candidate tumors for treatment with anti-HER2 antibody (trastuzumab therapy). PATIENT SUMMARY: Targeted therapy has a limited place in treatment of bladder cancer. In this study, human epidermal growth factor receptor 2 (HER2) overexpression in bladder carcinomas was evaluated in a large number of cases. Anti-HER2 therapy could be used in bladder cancers, as in breast and gastric cancers.