Intraoperative Histological Examination Research Articles

Epidermoid cyst of the coronal sulcus mimicking penile cancer: a case report

IntroductionEpidermoid cysts represent common benign tumors occurring anywhere in the body but very rarely in the penis. Only a few cases of penile localization have been reported in the literature so far, most of them being congenital and/or idiopathic, usually presenting in children as slow-growing, solitary, well-delimited cystic lesions. Here, we describe the case of a patient with a penile epidermoid cyst presenting as an ulcerated lesion of the coronal sulcus, thus mimicking penile cancer.Case presentationA 36-year-old Caucasian man presented with a three-month history of a rapidly growing asymptomatic ulcerated lesion in the ventral portion of the penile coronal sulcus. At surgical exploration, the area under the ulcerated lesion had a well-demarcated cystic shape; following its wide excision, an intraoperative histological examination revealed an epidermoid cyst. No recurrence had occurred at nine years of follow-up.ConclusionsRare benign tumors of the penis, like the described epidermoid cyst, may mimic cancer. Nevertheless, penile ulcerated lesions should always be surgically explored as wide excision and intraoperative histological examination remain the only means of obtaining a precise disease definition and, consequently, administering the appropriate treatment.

Smear technique for intraoperative diagnosis of central nervous system neoplasms

Background: Smear cytology has become increasily popular as an alternative to frozen section for the rapid diagnosis of most of central nervous system lesions. The aim of this study was to assess the utility of smear technique for the rapid diagnosis in the neurosurgical biopsies and to compare the smear cytological features with the final histopathological examination. Materials and Methods: This was a prospective study conducted in the Department of Pathology of BP Koirala Memorial cancer Hospital for a period of one year. Sixty cases of clinically suspected CNS tumors were sent for intraoperative smear cytological examination and histological examination. Both techniques were then compared for their ability to diagnose as well as grade the tumors. Results: Gliomas (51.6%) were the most frequently occurring tumors in the total cases. Diagnostic accuracy of squash/smear technique achieved was 88 %( 53/60) when compared with histopathological diagnoses. In two cases, smears comprised of blood clots and no opinion was possible in cytology. Complete discrepancy was seen in five cases that included two cases of atypical meningioma, a one case each of germinoma, glioblastoma and metastatic tumor. Conclusion: Smear technique is a fairly accurate, rapid, easily reproducible and cost effective tool to diagnose brain tumours. Smear cytology is of great value in Intraoperative consultation of central nervous system lesions. DOI: http://dx.doi.org/10.3126/jpn.v4i7.10296 Journal of Pathology of Nepal (2014) Vol. 4, 544-547

Primary osteosarcoma of the breast: A case report.

Osteosarcoma (OS) located in the breast is an extremely rare, malignant neoplasm. The current study presents the diagnostic process, treatment and follow-up of a 67-year-old female with OS of the breast. The diagnosis was made according to diagnostic imaging methods and microscopic examination with additional immunohistochemical staining. As a surgical treatment, tumourectomy with intraoperative histological examination and simple breast amputation was performed. No adjuvant chemotherapy was administered following surgery. Lung and bone metastases occurred without local recurrence 14 months following the surgery. In the present study, the details of the diagnostic examinations performed are evaluated and the consecutive phases of diagnostic and therapeutic proceedings are examined in comparison with the knowledge in the literature.

Isolated spinal Rosai–Dorfman disease misdiagnosed as lymphoplasmacyte-rich meningioma by intraoperative histological examination

Isolated spinal Rosai–Dorfman disease misdiagnosed as lymphoplasmacyte-rich meningioma by intraoperative histological examination

Unusual mucoepidermoid carcinoma of the liver misdiagnosed as squamous cell carcinoma by intraoperative histological examination

As rare condition, mucoepidermoid carcinoma may occur in liver although its etiology and pathogenesis is still unclear. We report here a case of intrahepatic mucoepidermoid carcinoma misdiagnosed as cholangiocarcinoma and squamous cell carcinoma by preoperative radiologic and intraoperative histological examinations, respectively. A 60-year-old woman presented with a 1-month history of progressive jaundice, epigastric discomfort, and weight loss with slightly increased carbohydrate antigen 19-9 (CA19-9). Computed tomography (CT) showed a large tumor, 8.0 cm in diameter, in the left lobe of the liver. A preliminary diagnosis of a cholangiocarcinoma of the liver was made. In the intraoperative histological examination, a diagnosis of squamous cell carcinoma was made based on predominantly invasive epidermoid cells with abundant keratinization and absence of mucin-producing cell component. However, postoperative histological diagnosis of the lesion was mucoepidermiod carcinoma of liver by thoroughly microscopical inspection and the presence of mucin-producing cells confirmed by Alcian blue staining. Despite surgical excision and chemotherapy, the tumor showed very aggressive malignancy with tumor recurrence. The patient died shortly afterward, surviving 6 months after surgery. Due to its rarity and distinct morphological features, mucoepidermoid carcinoma might be erroneously interpreted as squamous cell carcinoma by those who were not familiar with this condition in unusual locations. Therefore, removal of sufficient tissue from different portions of the lesion is essential for the surgeons and pathologists to make a precise diagnosis in the intraoperative histological examination.Virtual slideThe virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/4956311271136060

High false-negative proportion of intraoperative histological examination as a serious problem for clinical application of sentinel node biopsy for early gastric cancer: final results of the Japan Clinical Oncology Group multicenter trial JCOG0302

To evaluate the feasibility and accuracy of diagnosis using sentinel node (SN) biopsy in T1 gastric cancer, a multicenter trial was conducted by the Japan Clinical Oncology Group (JCOG). Sentinel node biopsy with indocyanine green (ICG) was performed in patients with T1 gastric cancer. Green-stained nodes (GNs), representing SNs, were removed first, and gastrectomy with lymphadenectomy was then performed. GNs in one plane (with the largest dimension) were histologically examined intraoperatively by frozen section with hematoxylin and eosin (H&E) stain. All harvested lymph nodes (GNs and non-GNs) were histologically examined by paraffin section after surgery. The primary endpoint was to determine the proportion of false negatives, which was defined as the number of patients with negative GNs by frozen section divided by those with positive GNs and/or positive non-GNs by paraffin section. The sample size was set at 1,550, based on the expected and threshold value as 5 and 10 % in the proportion of false negatives. Accrual was suspended when 440 patients were enrolled because the proportion of false negatives was high. In the primary analysis, the proportion of false negatives was 46 % (13/28) after a learning period with 5 patients for each institution. Seven of 13 patients had nodal metastases outside the lymphatic basin. False negatives remained at 14 % (4/28) even by examining additional sections of GNs by paraffin section. The proportion of false negatives was much higher than expected. Intraoperative histological examination using only one plane is not an appropriate method for clinical application of SN biopsy in gastric cancer surgery.

Nipple-areola-complex sparing mastectomy: five years of experience in a single centre

This study aimed at assessing the outcomes of nipple-areola-complex-sparing mastectomy (NSM) of breast cancer in a single-centre and single-surgeon series after 5 years of experience. From June 2007 to January 2012, 58 female patients with breast cancer were admitted for NSM at our unit and 55 of these underwent NSM. All patients underwent a preoperative clinical and instrumental evaluation. The clinical evaluation consisted of physical examination by taking measurements of the prosthesis and through anamnesis. The instrumental evaluation used were mammography, chest X-ray, abdominal and breast ultrasound, blood test and, if necessary, magnetic resonance imaging. Specific inclusion criteria have been met in recruiting patients: clinically negative axillas, tumours < 3 cm in any of the quadrants, tumours more than 1 cm away from the NAC. The patients underwent a surgical and oncological follow-up. The surgical follow-up consisted in treating wounds, managing drainages and tissue expanders and then planning the replacement surgeries. The oncological follow-up consisted of periodical medical (such as blood tests including cancer markers) and radiological evaluations (such as mammography, chest X-ray, abdominal and transvaginal ultrasound scan and/or thorax-abdomen computed tomography) to assess the disease progression, and, if necessary the patients underwent chemotherapy or hormonal therapy. Out of 58 recruited patients undergoing NSM, only 3 patients (5.1 %) had an occult tumour in the NAC at intraoperative extemporaneous histological examination and required the NAC removal. The other 55 patients (94.9 %) did not have neoplastic involvement of NAC and at an average follow-up period of 21.7 months (range 3-55 months) only 4 (7.2 %) had disease progression. Nipple-Sparing Mastectomy is a highly specialized and oncologically sure procedure to be performed only in reference centres on selected patients.

Bile duct damage after cold storage of deceased donor livers predicts biliary complications after liver transplantation

The aim of this study was to examine the development of biliary epithelial damage between organ retrieval and transplantation and its clinical relevance for patients. Common bile duct samples during donor hepatectomy, after cold storage, and after reperfusion were compared to healthy controls by hematoxylin and eosin (H&E) staining and immunofluorescence for tight junction protein 1 and Claudin-1. A bile duct damage score to quantify biliary epithelial injury was developed and correlated with recipient and donor data and patient outcome. Control (N=16) and donor hepatectomy bile ducts (N=10) showed regular epithelial morphology and tight junction architecture. After cold storage (N=37; p=0.0119), and even more after reperfusion (N=62; p=0.0002), epithelial damage, as quantified by the bile duct damage score, was markedly increased, and both tight junction proteins were detected with inappropriate morphology. Patients with major bile duct damage after cold storage had a significantly increased risk of biliary complications (relative risk 18.75; p<0.0001) and graft loss (p=0.0004). In many cases, the common bile duct epithelium shows considerable damage after cold ischemia with further damage occurring after reperfusion. The extent of epithelial damage can be quantified by our newly developed bile duct damage score and is a prognostic parameter for biliary complications and graft loss. Possibly, in an intraoperative histological examination, this bile duct damage score may influence decision-making in transplantation surgery.

Bilateral metastases of renal cell carcinoma to the ovaries – a case report

Renal cell carcinoma accounts for 75% of renal neoplasms. Clear cell carcinoma is diagnosed in about 80% of the cases. Renal cell carcinoma most frequently metastasizes to the lungs (50-60%), lymph nodes (36%), bones (30-40%), liver (30-40%), and brain (5%). In other organs the metastasis changes are observed very rarely. Ovarian metastases are found in 0.5% of renal cancers. So far, only 23 cases of renal cell carcinoma metastases to the ovary have been reported in the literature. In 18 cases they were metastases of renal cell carcinoma of the clear cell type. The authors present a case of a 50-year-old woman with double-sided metastatic changes to the ovary from renal cell carcinoma. The patient was admitted to the Gynecological ward with preliminary diagnosis of ovarian tumors. Gynecological examination revealed double-sided ovarian tumors, 6-7cm in diameter. Computed tomography also showed a 155 x 80 mm hetrogenous, multiform tumor localized above the uterus. In addition, CT showed a 75 x 55 mm tumor in the lower pole, and a smaller one, 15 mm in diameter in the upper pole of the right kidney. Laboratory tests were normal. The antigen Ca 125 was 25 j/ml. Mammography cytology gastroscopy colonoscopy were normal. The consulting urologist proposed a two-stage treatment. In the first stage, the removal of the double-sided ovarian tumors was proposed, while in the second stage the right nephrectomy was suggested. Double-sided ovarian tumors were found and removed (in the wall of the cyst- yellow, solid masses) during the first operation. Intraoperative histological examination showed changes with unknown grade of malignancy in both ovaries (number of studies QN 291). The patient underwent total hysterectomy. On day 5 postoperatively the woman was discharged from the hospital in good condition with the recommendation to pick up the histological test result in two weeks time. The final histological examination showed metastatic changes of renal cell carcinoma of the clear cell type (number of studies QN569-582, QN 585-608). The diagnosis of bilateral renal cell carcinoma metastases to the ovaries was confirmed by immunohistochemical studies using antibodies CD 10 and Vimentin (number of studies CT 1558-1559). The patient was directed to the Urological Ward. The surgery confirmed the presence of the tumor in the lower pole (about 8 cm in size), and a smaller one (about 1 cm in size) in the upper pole of the right kidney. The right nephrectomy was performed. Histological examination confirmed the primary clear cell renal cell carcinoma. The patient was directed to the next oncological treatment.

Factors affecting diagnostic yield in needle biopsy for brain lesions

Introduction. We analyse the factors that are associated with the diagnostic yield of needle brain biopsy. Material and methods. We present a retrospective series of 124 consecutive biopsies in a 30-month period. Patients’ demographics (age, gender), lesion topography (side, location, depth), lesion characteristics (histology, volume, radiological enhancement), type of biopsy procedure (freehand, ultrasound guided, frameless and frame-based stereotactic) and the use of intraoperative histologic examination were correlated with the diagnostic rate. Descriptive statistics and a nominal logistic regression model were used to evaluate the factors influencing diagnostic yield. Results. 63 men and 61 women were included in the study with mean age 59.2 (range: 16–86). 55 were frame-based stereotactic biopsies, 33 were frameless stereotactic biopsies, 29 biopsies were performed under ultrasound guidance and 7 freehand. The diagnostic yield in our series is 93.5%. The gender, lesion topography, biopsy method, use of intraoperative histology and enhancement did not correlate with the diagnostic yield. Younger age had a negative impact on diagnostic yield. 6 out of 8 inconclusive biopsies were in non-glial lesions (p < 0.05). The odds of obtaining a positive diagnosis increased sevenfold with every cc increase in lesion volume. Conclusion. The age of the patient, the volume and the histology of the brain lesion had an impact on the diagnostic yield of needle biopsy. None of the other factors significantly influenced the diagnostic rate.

Intraoperative Diagnosis Using Sentinel Node Biopsy with Indocyanine Green Dye in Gastric Cancer Surgery: An Institutional Trial by Experienced Surgeons

Reliable indicators that can intraoperatively determine the absence of nodal metastasis are in great demand to avoid unnecessary lymphadenectomy. However, little has been reported about the intraoperative diagnostic performance of sentinel node (SN) biopsy. Sentinel node biopsy by subserosal or submucosal injection of indocyanine green (ICG) was performed in 241 patients with American Joint Committee on Cancer tumor, node, metastasis staging system, 7th edition, clinical T1 (n = 190) and T2 (n = 51) gastric cancer by two experienced surgeons. All nodes that stained green (green node, GN), representing SNs, were excised before gastrectomy and were sliced into 2-mm sections for intraoperative histological examinations with hematoxylin and eosin staining. The sliced GNs were also examined simultaneously by imprint cytology. The GNs were detectable in 240 patients (3.8 ± 2.4 nodes per patient; range 1-17 nodes; median 3 nodes), and the success rate of detection was 99.6 % (240 of 241). Of 240 patients with a successful detection, 29 were found to have lymph node (LN) metastases; 16 were diagnosed with LN metastases in both GNs and non-GNs, 12 in GNs alone, and 1 in non-GNs alone. The false-negative rate based on the SN concept was 3.4 % (1 of 29). However, two patients with cT1 gastric cancer were diagnosed as intraoperative GN negative but were later confirmed as GN positive by histological examinations of paraffin sections. As an intraoperative diagnosis, the false-negative rate was 10.3 % (3 of 29). Sentinel node biopsy using ICG could be performed intraoperatively within reasonable limits under certain conditions, such as multiplanes for detection, combination use of imprint cytology, and open surgery by experienced surgeons.

Nonlinear Optical Microscopy for Histology of Fresh Normal and Cancerous Pancreatic Tissues

BackgroundPancreatic cancer is a lethal disease with a 5-year survival rate of only 1–5%. The acceleration of intraoperative histological examination would be beneficial for better management of pancreatic cancer, suggesting an improved survival. Nonlinear optical methods based on two-photon excited fluorescence (TPEF) and second harmonic generation (SHG) of intrinsic optical biomarkers show the ability to visualize the morphology of fresh tissues associated with histology, which is promising for real-time intraoperative evaluation of pancreatic cancer.Methodology/Principal FindingsIn order to investigate whether the nonlinear optical imaging methods have the ability to characterize pancreatic histology at cellular resolution, we studied different types of pancreatic tissues by using label-free TPEF and SHG. Compared with other routine methods for the preparation of specimens, fresh tissues without processing were found to be most suitable for nonlinear optical imaging of pancreatic tissues. The detailed morphology of the normal rat pancreas was observed and related with the standard histological images. Comparatively speaking, the preliminary images of a small number of chemical-induced pancreatic cancer tissues showed visible neoplastic differences in the morphology of cells and extracellular matrix. The subcutaneous pancreatic tumor xenografts were further observed using the nonlinear optical microscopy, showing that most cells are leucocytes at 5 days after implantation, the tumor cells begin to proliferate at 10 days after implantation, and the extracellular collagen fibers become disordered as the xenografts grow.Conclusions/SignificanceIn this study, nonlinear optical imaging was used to characterize the morphological details of fresh pancreatic tissues for the first time. We demonstrate that it is possible to provide real-time histological evaluation of pancreatic cancer by the nonlinear optical methods, which present an opportunity for the characterization of the progress of spontaneous pancreatic cancer and further application in a non-invasive manner.

Sentinel lymph node biopsy after neoadjuvant chemotherapy predicts pathological axillary lymph node status in breast cancer patients with clinically positive axillary lymph nodes at presentation

It is still controversial whether axillary lymph node (ALN) dissection (ALND) can be omitted after negative sentinel lymph node (SLN) biopsy (SLNB) in breast cancer (BC) patients with clinically positive ALNs at presentation treated with neoadjuvant chemotherapy (NAC). The study aim was to analyze whether SLNB could be useful in these patients. In a retrospective study, eligible patients were women with invasive BC with clinically positive ALNs at presentation, treated with NAC then a total or partial mastectomy, with an intraoperative histological examination of SLNs and non-SLNs suspicious for metastasis followed by ALND. Non-SLNs suspicious for metastasis were defined as hard or large nodes located in the same level of the axilla where clinically positive ALNs had been initially identified. The results of SLNB and clinicopathological characteristics were analyzed for correlation with pathological ALN status. In a consecutive series of 105 women with 107 BC cases, 81 (75.7 %) had at least 1 SLN, and the remaining 26 (24.3 %) had at least 1 non-SLN suspicious for metastasis. The intraoperative (or final) histological examination of these nodes revealed that the false-negative (FN) rate and accuracy were 8.2 (or 6.3) % and 95.1 (or 96.3) %, respectively. Estrogen receptor status at presentation, pathological tumor response, lymphovascular invasion after NAC, and NAC regimen were correlated with pathological ALN status. The histological examination of SLNs and that of non-SLNs suspicious for metastasis are useful for predicting pathological ALN status in BC patients with clinically positive ALNs at presentation who are treated with NAC.

Painful Nodules and Cords in Dupuytren Disease

The etiology of Dupuytren disease is unclear. Pain is seldom described in the literature. Patients are more often disturbed by impaired extension of the fingers. We recently treated a series of patients who had had painful nodules for more than 1 year, and we therefore decided to investigate them for a possible anatomical correlate. Biopsies were taken during surgery from patients with Dupuytren disease and stained to enable detection of neuronal tissue. We treated 17 fingers in 10 patients. Intraoperatively, 10 showed tiny nerve branches passing into or crossing the fibrous bands or nodules. Of 13 biopsies, 6 showed nerve fibers embedded in fibrous tissue, 3 showed perineural or intraneural fibrosis or both, and 3 showed true neuromas. Enlarged Pacinian corpuscles were isolated from 1 sample. All patients were pain free after surgery. Although Dupuytren disease is generally considered painless, we treated a series of early stage patients with painful disease. Intraoperative inspection and histological examination of tissue samples showed that nerve tissue was involved in all cases. The pain might have been due to local nerve compression by the fibromatosis or the Dupuytren disease itself. We, therefore, suggest that the indication for surgery in Dupuytren disease be extended to painful nodules for more than 1 year, even in the early stages of the disease in the absence of functional deficits, with assessment of tissue samples for histological changes in nerves.

Radioguided occult lesion localization plus sentinel node biopsy (SNOLL) versus wire-guided localization plus sentinel node detection: A case control study of 129 unifocal pure invasive non-palpable breast cancers

AimsWe compared histological patterns after lumpectomy for non-palpable breast cancers preoperatively localized by radioguided occult lesion localization plus sentinel node localization (SNOLL) versus wire-guided localization. MethodsTo ensure a homogeneously treated cohort and rigorous comparisons, only patients with invasive cancer and measurable opacity by imaging were included. Exclusion criteria were one or more parameters that could interfere with localization and/or the surgical procedure. Forty-three SNOLL were compared with 86 WGL plus sentinel node (SN) localization. Cancer localization effectiveness was based on careful assessment of histological data from only the first resected glandular specimen, as any additional resection specimens were guided by intraoperative histological examination. ResultsReexcisions to ensure free tissue margins were performed during the same procedure in 13.9% of SNOLL versus 31.3% of WGL; p = 0.02. Significantly more women in SNOLL (53.4%) also had free nearest margins of >9 mm after the first procedure compared with WGL (33.7%); p = 0.03. The median centricity ratio after the first procedure was better in SNOLL (2.8, range 1.3–14) than WGL (5, range 1–50); p = 0.008. The median number of SN detected by lymphoscintigraphy was the same in SNOLL and WGL (1, range 0–9, vs. 1, range 0–8). Intraoperative SN detection by blue dye and/or gamma probe was successful for 97.6% of SNOLL versus 93% of WGL. ConclusionIn this study, SNOLL was effective and safe, and this procedure significantly improved the rate of negative margins in the first specimen and the rate of reexcision for positive margins compared with WGL.

Highlights of Thirty-Year Experience of Laser Use at the Florence (Italy) Department of Dermatology

The CO2 laser has been used extensively in dermatological surgery over the past 30 years and is now recognised as the gold standard for soft tissue vaporization. Considering that the continuous wave CO2 laser delivery system and the newer “superpulsed” and scanned CO2 systems have progressively changed our practice and patient satisfaction, a long range documentation can be useful. Our experience has demonstrated that the use of CO2 laser involves a reduced healing time, an infrequent need for anaesthesia, reduced thermal damage, less bleeding, less inflammation, the possibility of intra-operative histologic and/or cytologic examination, and easy access to anatomically difficult areas. Immediate side effects have been pain, erythema, edema, typically see with older methods, using higher power. The percentage of after-treatment keloids and hypertrophic scars observed was very low (~1%) especially upon the usage of lower parameters. The recurrence of viral lesions (condylomas and warts) have been not more frequent than those due to other techniques. Tumor recurrence is minor compared with radiotherapy or surgery. This method is a valid alternative to surgery and/or diathermocoagulation for microsurgery of soft tissues. Our results are at times not consistent with those published in the literature, stressing the concept that multicentric studies that harmonization methodology and the patient selection are vital.

Genitourinary plexiform neurofibroma mimicking sacrococcygeal teratoma

Neurofibromatosis is a common inherited autosomal dominant disease, but genitourinary neurofibroma is rare. The unpredictable nature of neurofibromas has a serious impact on the quality of life of patients, and their management is challenging for clinicians. We present a 9-year-old girl with plexiform neurofibroma of genitourinary system associated with pulmonary hypertension, masquerading as sacrococcygeal teratoma. Intraoperative finding and histological examination of the resected tumor confirmed the diagnosis.

Meningioangiomatosis-associated meningioma misdiagnosed as glioma by radiologic and intraoperative histological examinations

As an extremely rare condition, meningioma may occur together with meningioangiomatosis. We report here a case of meningioangiomatosis-associated meningioma misdiagnosed as glioma by preoperative radiologic and intraoperative histological examinations. A 50-year-old woman presented with a 1-year history of headache and dizziness. Magnetic resonance imaging revealed a round left temporal mass located cortically with hypointensity on T(1)-weighted images and hyperintensity on T(2)-weighted images. In the intraoperative histological examination, a diagnosis of glioma was made based on high cellularity and large tumor cells with nuclear atypia. However, postoperative histological diagnosis of the lesion was meningioangiomatosis-associated meningioma corresponding to World Health Organization (WHO) grade I. A part of the cortical lesion showed the histological features of meningioangiomatosis. Neoplastic cells in the meningioma portion were a transitional variant with immunoreactivity to epithelial membrane antigen and low MIB-1 index, up to 1%. The patient has been followed up for 6months without adjuvant radiotherapy or chemotherapy. No tumor recurrence was found during this period. Meningioangiomatosis-associated meningioma might be erroneously interpreted as tumor invasion by those who were not familiar with this condition. Therefore, removal of sufficient tissue from different portions of the lesion is essential for the neuropathologist to make a precise diagnosis in the intraoperative histological examination.

A cystic meningioma misdiagnosed as malignant glioma by radiologic and intraoperative histological examinations

Cystic meningiomas are radiologically difficult to differentiate from malignant brain tumors, particularly when the tumors are intraparenchymally located. In such cases, a surgical strategy relies on intraoperative histological diagnosis. A 60-year-old man had a tumor with multiple cysts in the left parietal lobe that was diagnosed radiologically as malignant glioma. In operative findings, there was no dural attachment of the tumor, and the border between the tumor and normal brain tissue was unclear. Intraoperative histological examination supported the diagnosis of malignant glioma based on a high cellularity and an existence of a multinuclear giant cell in the tumor tissue. We finished the surgery with partial tumor resection; however, postoperative histological diagnosis of the tumor was a typical meningothelial meningioma showing characteristic whorl formations, and in conclusion, a definite diagnosis of the tumor was an intraparenchymal cystic meningioma. In further histological investigations, the tumor tissue around cysts exhibited significantly different features from meningothelial meningioma, demonstrating small lymphocytes and histiocytes with a large nucleus, which resembled intraoperative histological findings. We deliberated that the removal of the tumor tissue from the degenerated portion for intraoperative histological examination might lead to the misdiagnosis of malignant glioma. Operative strategy is strongly influenced by intraoperative histological diagnosis. Therefore, surgeons are obliged to facilitate more precise intraoperative histological examinations by obtaining sufficient tissue from different parts of the tumor.

A giant retroclival Rathke’s cleft cyst

Rathke's cleft cyst (RCC) is a rare sellar tumor that can extend to the retroclival region, resulting in brain stem compression. We report a male with short stature who experienced repeated syncope due to compression of the brain stem by a giant retroclival RCC. MRI revealed a large homogeneous sellar tumor with anterior displacement of the pituitary gland that extended to the left retroclival space. The tumor differed from ordinary RCCs because of its unusual clinical presentation, the direction of extension, and its imaging characteristics. The retromastoid surgical approach was used for cyst marsupialization. Intraoperative appearance and histological examination confirmed the diagnosis. A follow-up MRI, 2years after resection of the cyst, showed no recurrence.