ALK-rearranged renal cell carcinoma (ALK-RCC): Evaluation of histomorphological and immunohistochemical features by analysis of 276 renal cell carcinoma cases in Turkey.

Anaplastic lymphoma kinase (ALK) rearrangement-associated renal cell carcinoma (ALK-RCC) is characterized by ALK fusion at chromosome 2p23. It has recently been included as a recognized entity with the 5th edition of the WHO classification urinary and male genital tumor. However, our knowledge about ALK-RCC is limited due to the small number of reported cases. In our study, we aimed to contribute the histomorphological and immunohistochemical features of ALK-rearranged renal cell carcinoma cases. We reviewed 276 cases diagnosed as RCC in order to detect ALKRCCs.We used immunohistochemistry to screen ALK rearrangement and then confirmed the ALK rearrangement by fluorescence in situ hybridization (FISH) method. ALK was immunohistochemically positive in 8 of 276 cases. ALK rearrangement was detected by FISH in 3 of 8 cases. These cases were previously diagnosed as clear cell renal cell carcinoma (CRCC), papillary renal cell carcinoma (PRCC), and chromophobe renal cell carcinoma (ChRCC). Their histomorphological findings were diverse, and all three cases exhibited different immunohistochemical findings. Survival of these patients ranged between 6 and 24 months. ALK immunohistochemical findings were also different in each case as perinuclear, weak cytoplasmic, and membranous.ALK RCCs appear to be very rare tumors with heterogeneous histomorphological and immunohistochemical features. Although immunohistochemistry may be useful to detect ALK positivity, genetic evaluation is required to confirm the diagnosis. With identifying ALK-RCCs, ALK inhibitors, which are currently used in the treatment of lung adenocarcinomas, can be used as a targeted therapy option in ALK-RCCs.

Effect of Extractum cepae, heparin sodium and allantoin combination (ContractubexTM) on adhesion and fibrosis after neck surgery (thyroidectomy) in rats.

OBJECTIVE: Reoperative thyroid surgery is technically difficult process with increased complications due to the adhesions and fibrosis caused by the previous surgery. In this experimental animal model, we planned to investigate the effect of ContracttubexTM, a mixture of Extractum cepae, Heparin sodium and Allantoin, on adhesion and fibrosis after neck surgery (thyroidectomy). METHODS: The current study is an experimental animal model of post-thyroidectomy adhesion. Twelve Wistar-Albino male rats in two groups were used. Under sterile conditions, a midline incision on the neck was made. The anterior thyroid muscles were separated and the thyroid lodge was reached. As a minor interventional procedure, a sponge was applied to the thyroid tissue, and then a combination of 1 g Extractum capae, heparin, sodium, and allantoin was applied to the dissection site in the drug group. Rats in both groups were sacrificed on 30th day. Cervical regions were dissected and evaluated for macroscopic adhesion. Tissue samples were taken for microscopic evaluation for fibrosis and inflammation. RESULTS: In the experimental group in which ContractubexTM was applied, inflammation was not detected in five (83.3%) of six rats while no inflammation was detected in four (66.7%) of six rats in the control group (p=0.505). Considering the fibrosis score, mild or moderate fibrosis was detected in four (66.7%) of six rats in the control group, while fibrosis was found in only two (33.3%) rats in the experimental group (p=0.264). When macroscopic adhesion was evaluated, two (33.3%) rats of the control group subjects were Grade 4, and one (16.7%) was Grade 3. No rats in the experimental group were Grade 4 (p=0.392). CONCLUSION: ContractubexTM seems to be effective in preventing adhesions and fibrosis after thyroidectomy and neck surgery, but further research is needed for use in human studies.

Effects of transcutaneous electrical nerve stimulation on rats with post-operative ileus.

BACKGROUND: Post-operative ileus (POI) is a type of bowel dismotility causing accumulation of gas and fluid. Transcutaneous electrical nerve stimulation (TENS) has been frequently used for medical applications such as pain treatment and nervous stimulation. In this experimental animal model of POI, our aim is to investigate the effects of TENS on POI, and to demonstrate histopathological changes in rat intestine after TENS application. METHODS: The present study is an experimental animal model of POI. Sixteen Wistar-Albino male rats in two groups were used and laparotomy was performed. After colorectum and small intestine were manipulated, activated charcoal and Nile red were ad-ministered by oral gavage. Electrodes were placed to the abdomen skin of the rats and TENS method was used. Rats in two groups were sacrificed on 24 h. The esophagus, stomach, and all intestines of the rats were resected and a direct X-ray and computerized tomography scan, and 'J' images were taken, and the progression of active coals was measured radiologically. Histopathological and microscopic evaluation was performed. RESULTS: The median of activated charcoal measure was 429 mm (178-594) in TENS group, 203 mm (149-313) in the control group, respectively, and these were statistically significant (p=0.004963). There was a significant difference between the two groups in terms of histopathological necrosis (p=0.041). In addition, the amount of Nil Red (550 nm) in the GI track is increased after 8 h of gavage with sequential applications of TENS. CONCLUSION: This study demonstrated the protective and therapeutic efficacy of TENS in POI in a rat model by radiologically and histopathologically. In clinical practice, TENS may be examined on POI. Further studies are warranted to validate and generalize our findings, and to assess the impact of TENS for post-operative pain also.

Neuroprotective Effects of Dexpanthenol on Rabbit Spinal Cord Ischemia/Reperfusion Injury Model.

OBJECTIVE: Dexpanthenol (DXP) reportedly protects tissues against oxidative damage in various inflammation models. This study aimed to evaluate its effects on oxidative stress, inflammation, apoptosis, and neurological recovery in an experimental rabbit spinal cord ischemia/reperfusion injury (SCIRI) model. METHODS: Rabbits were randomized into 5 groups of 8 animals each: group 1 (control), group 2 (ischemia), group 3 (vehicle), group 4 (methylprednisolone, 30 mg/kg), and group 5 (DXP, 500 mg/kg). The control group underwent laparotomy only, whereas other groups were subjected to spinal cord ischemia by aortic occlusion (just caudal to the 2 renal arteries) for 20 min. After 24 h, a modified Tarlov scale was employed to record neurological examination results. Malondialdehyde and caspase-3 levels and catalase and myeloperoxidase activities were analyzed in tissue and serum samples. Xanthine oxidase activity was measured in the serum. Histopathological and ultrastructural evaluations were also performed in the spinal cord. RESULTS: After SCIRI, serum and tissue malondialdehyde and caspase-3 levels and myeloperoxidase and serum xanthine oxidase activities were increased (P < 0.05-0.001). However, serum and tissue catalase activity decreased significantly (P < 0.001). DXP treatment was associated with lower malondialdehyde and caspase-3 levels and reduced myeloperoxidase and xanthine oxidase activities but increased catalase activity (P < 0.05-0.001). Furthermore, DXP was associated with better histopathological, ultrastructural, and neurological outcome scores. CONCLUSIONS: This study was the first to evaluate antioxidant, anti-inflammatory, antiapoptotic, and neuroprotective effects of DXP on SCIRI. Further experimental and clinical investigations are warranted to confirm that DXP can be administered to treat SCIRI.

Effects of Topical Ozone Application on Outcomes after Accelerated Corneal Collagen Cross-linking: An Experimental Study.

PURPOSE: Ozone is a trioxygen molecule that spontaneously degrades into oxygen and oxygen free radicals. This study was designed to assess the effects of topical ozone application on outcomes after corneal collagen cross-linking (CXL). METHODS: Enucleated fresh cadaver yearling sheep eyes (n = 28) were divided into five groups: control (C, n = 6), sham (S, n = 6), ozone only (Z, n = 6), CXL only (X, n = 5), and Ozone + CXL (ZX, n = 5). In all groups, except C, the epithelial layer was removed. In group Z, 20 µg/mL liquid ozone was topically applied. In group X, CXL was performed in the accelerated pulse mode. In group ZX, both CXL and ozone were applied. Post-interventional oxygen levels were determined and corneal confocal microscopy and optical coherence tomography were performed. Corneas were evaluated using light and electron microscopy. RESULTS: Pre-interventional central corneal thickness (CCT) was highest in the control group and considerably similar in the remaining groups (P = 0.006). Pre- and post-interventional CCT were significantly different in the ozonated groups (Z and ZX) (P = 0.028; P = 0.043). Demarcation line depths were similar in groups Z, X, and ZX (P = 0.343). Increased stromal tissue reflectivity was observed in groups Z, X, and ZX. Oxygen levels were higher in the ozonated groups (Z and ZX) (P = 0.006), and caspase activity was higher in the CXL groups (X and ZX) (P = 0.028) as compared to the other groups. Group ZX showed tighter, more regular, and parallel fibrils. CONCLUSION: Ozone increases corneal stromal oxygenation which can probably augment the effect of CXL. Future studies should investigate the safety and feasibility of ozone application during CXL.

A first time report on the coocurrence of sarcoidosis and ALK(-) CD30(+) anaplastic large cell lymphoma that is highly responsive to brentuximab vedotin treatment.

Sarcoidosis is known to be associated with higher incidence of solid tumors and hematological malignancies. ALK(-) CD30(+) anaplastic large cell lymphoma is a type of non-Hodgkin lymphoma showing poor prognosis, and seldom co-occurs with sarcoidosis. As this rare and highly mortal disease did not respond to classical chemotherapies and showed remission with brentuxumab vedontin treatment, we are presenting our first case reported from Turkey hoping to contribute to the literature.

An evaluation of the effect on lower extremity fracture healing of collagen-based fusion material containing 2 different calcium phosphate salts: An experimental rat model.

BACKGROUND: Collagen-based synthetic bone grafts which contain tricalcium phosphate (TCP) and hydroxyapatite (HA), and collagen-based synthetic bone grafts containing only TCP have some advantages compared to autografts. Therefore, these grafts are frequently used to fill bone defects and pseudoarthrosis. OBJECTIVES: The aim of this study was to evaluate and compare the clinical, radiological and histopathological effects of TCP-HA and TCP alone + Type-1 collagen in healing lower extremity fractures in a pseudoarthrosis model in rat femurs. MATERIAL AND METHODS: A total of 36 female Wistar rats were randomly separated into 4 groups. Group 1 (n = 10) was the control group. A femur pseudoarthrosis model was created in Groups 2, 3 and 4. On the 90th day after the 1st surgery in Group 2 (n = 10), TCP-HA + Type-1 collagen was applied, in Group 3 (n = 10), TCP alone + type-1 collagen was applied, and in Group 4 (n = 6, the placebo group), saline solution was applied. Fixation was performed with an intramedullar pin. After 60 days and clinical and radiological scoring, all animals were sacrificed and a histopathological evaluation of the pseudoarthrosis areas was conducted. RESULTS: In all the clinical, radiological and histopathological measurements used in the evaluations of the differences between the groups, a higher rate of union was determined in Group 2 (TCP-HA). No significant difference was determined between Group 3 and Group 4 in terms of union rates. CONCLUSIONS: The clinical, radiological and histopathological results of this study showed that TCP alone was less effective than TCP-HA in the union of a femur pseudoarthrosis model in rats. The reason for this difference was considered to be hydroxyapatite (HA).

Lhermitte-Duclos Disease: A Rare Lesion with Variable Presentations and Obscure Histopathology.

Since Lhermitte-Duclos is a quite rare disorder with both neoplastic and hamartomatous features, clinical and pathological diagnosis can sometimes be challenging. For the pathologist it is of extreme importance to be aware of variable clinical and histopathological presentations of such a rare lesion particularly to differentiate it from the low-grade glial and neuronal tumors. We present four cases of Lhermitte-Duclos in a histopathological perspective. Although enlargement of the internal granular layer of the cerebellum is a consistent finding in our cases, morphological severity was highly variable and in some cases the enlargement was insignificant. Frozen sections of one case did not reveal diagnostic findings. The vacuolar change observed in the paraffin sections was obscure in the frozen. Pathological diagnosis of Lhermitte-Duclos disease can be extremely difficult in the absence of proper clinical information and the pathologist should be watchful for any irregularity in the internal granular layer in evaluating the cerebellar tissue which is otherwise normal.

Is testis-sparing surgery safe in small testicular masses? Results of a multicentre study.

INTRODUCTION: Our goal was to evaluate benign and malignant lesions and testicular intraepithelial neoplasia (TIN) in the neighbouring normal-appearing testis tissue in men who underwent radical orchiectomy for testicular mass with a pathologic tumour size of ≤3cm. METHODS: In this retrospective, multicentre study, data of 252 patients from 11 different institutions were included. Patients were divided into three groups based on tumour size: Group 1 (0-1 cm; n=35), Group 2 (1.1-2cm; n=99), and Group 3 (2.1-3 cm; n=118). Benign lesions and TIN were sought in the neighbouring testicular tissue and compared between groups. RESULTS: Mean patient age was 32.3 years. Benign lesions were reported in 54.3%, 33.3%, and 14.4% of Groups 1, 2, and 3, respectively (p<0.05 between groups). TIN was detected in 20%, 42.4%, and 41.5% of Groups 1, 2, and 3, respectively (p<0.05 for Group 1 vs. Groups 2 and 3; p>0.05 for Groups 2 vs. 3). Multifocality was detected in 8.6%, 4%, and 0% of Groups 1, 2, and 3, respectively (p<0.05 for both Group 1 vs. Group 3 and for Group 2 vs. Group 3; p>0.05 for Group 1 vs. Group 2). A tumour cutoff size of 1.5 cm was found to be significant for detecting benign tumour. TIN and multifocality rates were similar in patients with a tumour size of ≤1.5 vs. >1.5 cm (p>0.05). CONCLUSIONS: Benign lesions and TIN in the neighbouring testis were significantly decreased and multifocality was increased in patients with a tumour mass size of ≤1 cm. Testis-sparing surgery should be performed with caution and a safety rim of normal tissue should also be excised.

Is the use of hemostatic matrix (Floseal) and alkylene oxide copolymer (Ostene) safe in spinal laminectomies? Peridural fibrosis assessment.

OBJECTIVE: Failed Back Syndrome (FBS) is unacceptable relief of pain or recurrence of symptoms in patients after spinal surgery, such as laminectomy. One possible cause of FBS is peridural fibrosis (PF). PF is the overproduction of scar tissue adjacent to the dura mater. Bleeding can cause PF after laminectomy. Ostene is an alkylene oxide copolymer material used to stop bleeding from bony surfaces. Floseal is a gelatin thrombin matrix sealant used to assist fibrin formation and to promote coagulation. METHODS: Total of 32 female Sprague-Dawley rats were evenly allotted to 4 experimental groups: laminectomy only, laminectomy + Ostene (Baxter International, Inc., Deerfield, IL, USA), laminectomy + Floseal (Baxter International, Inc., Deerfield, IL, USA), and laminectomy + Adcon-L (aap Implantate AG, Berlin, Germany). After performing total laminectomy, agents were placed over dura mater. Spinal column of test subjects was harvested 6 weeks after laminectomy. Histopathological examination of samples was based on Masson's trichrome and hematoxylin and eosin staining. PF observed in the groups was graded using system previously described by He et al. Statistically significant p value was defined as p < 0.005. RESULTS: Present study revealed that Adcon-L, Ostene, and Floseal groups had reduced PF compared with laminectomy only group (p = 0.001). Comparison of Ostene and Floseal groups with Adcon-L group yielded no significant difference. CONCLUSION: Reoperation as result of FBS has greater risk and often has poor outcome; surgeons must take precautions to avoid FBS, such as careful selection of appropriate patient and operation technique. Ostene and Floseal may be applied and left in the operation field safely during laminectomy to reduce occurrence of PF after procedure.

Effects of Topical Cova™, Tisseel® and Adcon® Gel Application on the Development of Spinal Peridural Fibrosis: An Experimental Study in Rats.

AIM: Leptomeningeal adhesions and fibrosis in the spinal peridural space are the most common causes of post-laminectomy syndrome. Fibrin sealant agents and membrane barriers are commonly used for hemostasis and sealing purposes in spinal surgery. Peridural fibrosis may be a risk of the usage of these topical agents. In this study, we aimed to compare the effects of Cova ™, Tisseel® and Adcon ® Gel on the development of spinal peridural fibrosis in the experimental rat model. MATERIAL AND METHODS: Thirty-two Sprague Dawley female rats were randomly divided into 4 groups. Groups were constituted as group 1; Cova™ group (laminectomy+Cova™), group 2; Tisseel® group (laminectomy+Tisseel®), group 3; Adcon®Gel group (laminectomy + Adcon®Gel), group 4; control group (laminectomy only). Six weeks after laminectomy, spinal columns were removed en bloc between L1 and L4 vertebrae. Peridural fibrosis was evaluated histologically and the results were compared statistically. RESULTS: Statistically significant reduction of peridural fibrosis was achieved in groups 1, 2, and 3 when compared with the control group (p < 0.05). Our data revealed a statistically significant difference between group 1 and group 3 (p < 0.05). When we compared with group 2 and 3, the fibrosis grades were not different between these two groups (p > 0.05). CONCLUSION: Fibrin sealant agent Tisseel® and membrane barrier Cova™ do not enhance peridural fibrosis following laminectomy. Cova™ and Tisseel® may be appropriate for hemostasis and leakage prevention during the spinal surgery and it is safe to leave these materials on the operation surface.

Claudin-1 expressions decrease in pterygium with respect to normal conjunctiva.

CONTEXT: Pterygium is the fibrovascular growth of the limbal conjunctiva over cornea. This proliferative nature might have a pathogenesis associated with tight junction proteins. OBJECTIVE: To investigate the tight junction protein claudin-1 expressions in pterygium with respect to normal conjunctiva. MATERIALS AND METHODS: This retrospective study included 28 patients who underwent pterygium surgery with autograft. Claudin-1 expressions were immunohistochemically evaluated in normal and lesional conjunctiva of the same eye. Immunohistochemical evaluation was done with regard of both the intensity and the extent of staining. The distribution of the immunohistochemical scores in pterygium and normal conjunctiva has been compared with using McNemar test. RESULTS: The mean age of the patients was 52.2 ± 11.2 years and male/female ratio was 8/20. Among 28 samples of normal conjunctiva 25 (89.2%) demonstrated a strong immunohistochemical expression with claudin-1 whereas this rate was 10.8% for pterygium samples. Statistical analysis revealed a significant decrease in claudin-1 expressions in pterygium with respect to normal conjunctiva (p < 0.001). DISCUSSION AND CONCLUSIONS: The loss of claudin-1 appears to be involved in the pathogenesis of pterygium and the future studies will elucidate the exact role of tight junction proteins in the invasive and recurrent nature of pterygium.

Corticosteroid pre-treated primary CNS lymphoma: a detailed analysis of stereotactic biopsy findings and consideration of interobserver variability.

Prior corticosteroid therapy presents a major challenge in the diagnosis of CNS lymphomas, particularly in stereotactic biopsies. In this study we analysed the cytological, histopathological and immunohistochemical features in stereotactic biopsies of 25 primary CNS lymphoma cases pre-treated with corticosteroids. We documented the extent and the frequency of each finding. We also investigated the significance of subjectivity in evaluation of these biopsies in 3 seperate sessions including the final diagnostic decision. In 48% of our cases the diagnosis was straightforward. These cases were characterized by prominent blasts either in diffuse paranchymal infiltrates or in perivascular regions. The remaining 52% demonstrated some degree of variability among pathologists. Lymphoid atypia other than the typical blastic morphology appeared as a subjective finding and this was more pronounced in cytology preparations. In our study, corticosteroid pre-treatment in primary CNS lymphoma was associated with a large spectrum of histopathological, immunohistochemical and cytological findings. Combined use of an extended immunohistochemical panel would increase the possibility of conclusive diagnosis. Nevertheless some of these findings and therefore the diagnosis are open to subjectivity.

Decrease in serine protease HtrA1 expression correlates with grade and recurrence in meningiomas.

PURPOSE: HtrA1 is a serine protease which was shown to be down-regulated in a variety of human cancers. It is considered to be a tumor suppressor and suggested as a prognostic marker and a therapeutic candidate. In order to investigate any possible implication of HtrA1 in meningioma we studied 100 cases. MATERIAL/METHODS: We used immunohistochemistry to determine HtrA1 expression in tumor tissue. Expression levels were evaluated with respect to tumor grade and recurrence. RESULTS: Our data revealed a strong association between decrease in HtrA1 expression and increase in meningioma grade (p=0.005). Most importantly, patients with higher HtrA1 expression had a lower rate of recurrence (p<0.001). CONCLUSIONS: According to our results HtrA1 appeared as an immunohistochemical marker to predict behaviour of the meningioma, mainly the recurrence. Although the exact mechanisms of HtrA1 are still largely unknown, we think that further in vivo and in vitro studies explaining the molecular targets of HtrA1 would have a great importance with regard to its role as a therapeutic agent for meningioma.

Pleomorphic adenomas of the parapharyngeal space.

Background. Parapharyngeal space is one of potential facial planes for neoplasms and infections and represents less than 1% of all head and neck tumours. Occurrence of the pleomorphic adenoma in the parapharyngeal space is a rarity. Case Presentation. Here, three giant pleomorphic adenomas of different sizes occupying the parapharyngeal space in three patients are reported. Extensive preoperative diagnostic workup was done in order to verify the nature and size of the tumour and the proximity to the large vessels. Review of the literature, clinical features, pathology, radiological findings, and treatment of these tumours are discussed. Conclusion. The excision of the tumor through submandibular transcervical approach, without cutting the mandible, turned out to be a safe and radical approach in all three cases.

Clinical outcome of adult choroid plexus tumors: retrospective analysis of a single institute.

BACKGROUND: Choroid plexus tumors are rare brain tumors with clinical features that vary according to the histological grade. We reviewed the treatment outcomes of 15 adult patients with choroid plexus tumors, focusing on surgical outcomes and current therapeutic strategies. METHOD: Patient demographic and clinical characteristics, operative findings, adjuvant therapies, disease progression and survival rates were reviewed. RESULTS: The median age at diagnosis was 33.7 ± 10 years (19-59 years) for patients with choroid plexus tumors. Postoperative chemotherapy was given to 26.7 % of patients, and 13.3 % of patients received radiotherapy. The Ki-67 labeling index and mitotic index increased at higher histological grades. All of the choroid plexus papilloma and atypical choroid plexus papilloma patients have survived. The overall survival rate of patients with choroid plexus carcinoma was 50 % in the first year, but none of the patients survived to the second year. Five patients underwent permanent cerebrospinal fluid diversion surgery because of hydrocephalus or subdural effusion. CONCLUSIONS: Choroid plexus papilloma and atypical choroid plexus papilloma patients can be treated with complete surgical resection. Choroid plexus carcinoma has a poor prognosis, and aggressive multi-modal treatments are generally needed for treatment. Chemotherapy and radiotherapy are important adjuvant therapies for choroid plexus carcinoma. If hydrocephalus and/or subdural effusion occur, permanent cerebrospinal fluid (CSF) diversion should be added to the therapeutic strategy.

Osteopontin expressions correlate with WHO grades and predict recurrence in meningiomas.

Recurrence of meningiomas is a major prognostic issue. Although World Health Organization (WHO) histopathological grading correlates strongly with recurrence, it has some limitations, and predicting the biological behavior of grade I meningiomas is particularly difficult. Osteopontin (OPN) is a protein known to be involved in tumor progression. The purpose of this study is to determine expression of OPN in meningiomas and to investigate its correlation with WHO grades and tumor recurrence. Immunohistochemical (IHC) evaluation of expression of OPN was performed by two different methods to ensure reliability. OPN IHC and Allred scores were calculated on the basis of intensity and extent of staining. Both scores were in agreement and correlated significantly with meningioma grade and Ki-67 index. OPN scores were also significantly correlated with recurrence of WHO grade I meningiomas. Cut-off values for OPN IHC and OPN Allred scores between non-recurrent and recurrent grade I meningiomas were calculated as 70 and 5.5 respectively. We concluded that OPN is a valuable marker for grading meningiomas and for predicting the recurrence in WHO grade I tumors.

L'hermitte-Duclos disease in an elderly patient: A case report and review of the literature.

L'hermitte-Duclos disease (LDD) is an extremely rare cerebellar lesion of uncertain etiology. Occasionally, the patients with LDD may even have sudden neurological deterioration due to acute heniation as seen in the present case report. It is also imperative to distinguish this disease from other malignant lesion of the cerebellum and cerebellar malformations with its varied natural course of history and hence better ability to prognosticate such patients. Herein, we reported a successfully treated case of LDD following a long history of vaguely defined neurological complaints in an elderly patient and reviewed the literature.

Solitary fibrous tumor of neck mimicking cold thyroid nodule in 99m tc thyroid scintigraphy.

A 68-year-old man had a rapidly growing, painless neck mass, thought to be nodular goiter. Ultrasonography showed a giant, heterogeneous mass occupying the middle and superior poles and protruding outside of the left thyroid lobe. The results of the thyroid function tests were normal. Thyroid scintigraphy revealed a large hypoactive nodule in the left thyroid lobe. Complete surgical removal of tumor was performed and macroscopically demonstrated a well-demarked lesion outside the thyroid gland. Microscopically, the lesion was composed of fibroblast-like spindle cells in a patternless architecture and extensive stromal hyalinization. Immunohistochemistry showed positive reaction for CD34 in spindle cells and diffuse bcl-2 staining. The pathology was confirmed as solitary fibrous tumor. In the follow-up period after surgery, thyroid scintigraphy showed normal left thyroid lobe. Solitary fibrous tumor originated from or associated with thyroid gland is extremely rare. According to our knowledge, this is the first reported solitary fibrous tumor presenting like a cold thyroid nodule. This pathology must be considered for differential diagnosis of neck masses in the thyroid region.

Stromal expression of CD34, α-smooth muscle actin and CD26/DPPIV in squamous cell carcinoma of the skin: a comparative immunohistochemical study.

Invasion pathogenesis is one of the most complicated issues in the literature. There are numerous studies concerning the tumor markers implicated in the preinvasive-invasive tumor sequence. Despite ample studies on the invasion pathogenesis of cutaneous melanomas, there is limited and dispersed work presently available on non-melanoma skin cancer. The vast knowledge in the literature concerning this issue in squamous cell carcinoma comes mostly from the studies of the oral cavity, esophagus, larynx, and cervix. In this study, we investigated tumor-free neighboring stroma and tumor stroma in squamous cell carcinomas (SCCs) of the skin as well as keratoacanthomas (KAs) with respect to the presence of stromal CD34-positive (CD34+) fibrocytes and α-smooth muscle actin-positive (α-SMA+) myofibroblasts using seborrheic keratosis (SKs) and non-tumoral skin samples as controls. We also evaluated the stromal expression pattern of CD26/DPPIV (CD26), a tumor suppressor gene product that also has immunoregulatory properties. Immunohistochemistry was performed on samples of 31 SCC, 8 KA, 15 SK and 10 non-tumoral skin samples. Peri-tumoral stroma from resection margins was also evaluated. We found that CD34 and α-SMA demonstrated significantly different staining between benign and malignant squamous skin lesions consisting of a loss of CD34+ fibrocytes paralleled by a gain of α-SMA+ myofibroblasts in malignant tumor stroma. Additionally, it was shown that CD26 expression was lower in tumor stroma when compared to that of tumor neighboring stroma. However, we concluded that this finding may be attributable to the solar elastosis areas in the peritumoral tissue, which shows diffuse strong positivity for this marker.