Low-grade cylindromatous adnexal carcinoma with unusual histopathological features: report of a case with comparative immunohistochemical study and meta-analysis of the literature.

We present an extremely rare case of low-grade cylindromatous adnexal carcinoma (CAC) on the right chest wall of a 77-year-old man. Histopathologically, the neoplasm was initially diagnosed as a cylindroma that developed over the course of 13 years. A diagnosis of low-grade CAC was rendered after the documentation of a local recurrence and histopathology of the recurrent tumor. To further assess the evolution of low-grade CAC over time, we compared the morphology, mitotic account, proliferative markers and adhesion molecule immunoreactivity among paired primary and recurrent tumors. Unlike those earlier reported, our case showed the maintenance of tumor morphology after a recurrence without areas of obvious malignant transformation or metaplastic change. We showed here for the first time the expression of adhesion molecules of CAC/spiradenoma and a comparison of proliferation indices between a primary tumor and its local recurrence. This peculiar tumor differs from previously reported cases and harbors a malignant potential although the histopathological features of malignancy are subtle. Our meta-analysis of the literature provided background information regarding this rare entity. Alterations of E-cadherin and GCDFP-15 expression may provide additional helpful clues in differential diagnosis and determining the clinical behavior of this unusual neoplasm. Further studies are warranted to confirm the potential discriminative role of these markers.

Pediatric allergies in Japan: Coronavirus disease pandemic-related risk factors.

Background: The coronavirus disease 2019 (COVID-19) pandemic impacted various parts of society, including Japanese children with allergies. Objective: This study investigated risk factors for pediatric allergic diseases associated with the state of emergency owing to the COVID-19 pandemic in Japan, including during school closures. Methods: Parents of pediatric patients (0-15 years) with allergies were enrolled and queried regarding the impact of school closure on pediatric allergies compared to that before the COVID-19 pandemic. Results: A valid response was obtained from 2302 parents; 1740 of them had children with food allergies. Approximately 4% (62/1740) of the parents reported accidental food allergen ingestion was increased compared to that before the COVID-19 pandemic. Accidental ingestion during school closures was associated with increased contact with meals containing allergens meant for siblings or other members of the family at home. The exacerbation rate during the pandemic was highest for atopic dermatitis at 13% (127/976), followed by allergic rhinitis at 8% (58/697), and bronchial asthma at 4% (27/757). The main risk factors for worsening atopic dermatitis, allergic rhinitis, and bronchial asthma were contact dermatitis of the mask area (34/120 total comments); home allergens, such as mites, dogs, and cats (15/51 total comments); and seasonal changes (6/25 total comments), respectively. Conclusion: The main factors affecting allergic diseases were likely related to increased time at home, preventive measures against COVID-19, and refraining from doctor visits. Children with allergies were affected by changes in social conditions; however, some factors, such as preventing accidental ingestion and the management of allergens at home, were similar to those before the COVID-19 pandemic. Patients who had received instructions on allergen avoidance at home before the pandemic were able to manage their disease better even when their social conditions changed.

Myxoid type and non-myxoid type of intimal sarcoma in large vessels and heart: review of histological and genetic profiles of 20 cases.

Intimal sarcoma is one of the most common and well-known primary malignant neoplasms of the aorta and heart. The authors reviewed cases of intimal sarcoma from histological, immunohistochemical and genetic perspectives. Twenty cases of intimal sarcoma were retrieved. Immunohistochemistry and FISH of MDM2 and PDGFRA genes were performed. All 20 tumours were composed of spindle-shaped, stellate, oval or polygonal tumour cells with irregular hyperchromatic nuclei arranged in a haphazard pattern, accompanied by nuclear pleomorphism and frequent mitotic figures. Other histological findings were as follows: abnormal mitosis in 10 cases (50%), necrosis in 15 cases (75%), myxoid stroma in 12 cases (60%), cartilaginous formation in 1 case (5%), haemorrhage in 12 cases (60%) and fibrinous deposition in 14 cases (70%). The tumours were positive for MDM2 in 16 cases (80%), ERG in 4 cases (20%), alpha-smooth muscle actin in 6 cases (30%), desmin in 5 cases (25%) and AE1/AE3 in 4 cases (20%). Immunohistochemical positivity was focal in each case. Loss of H3K27me3 expression was noted in 2 cases (10%). MDM2 and PDGFRA gene amplifications were detected in 11 cases (55%) and 1 case (5%), respectively. Fisher's exact test revealed a significant correlation between MDM2 gene amplification and myxoid stroma (p = 0.0194). No parameters showed any association with the anatomical location of the tumours. It was suggested that myxoid histology of intimal sarcoma may be associated with MDM2 gene amplification and that intimal sarcoma may be divided into myxoid and non-myxoid types.

Benign nodular goiter with spindle cell component.

We report three benign nodular goiters associated with spindle cell component. The spindle cells were bland, and showed short fascicular pattern or formed small nests. The cytoplasm was pale or clear. A transition between follicular cells and the spindle cells was observed. Immunohistochemically, they were positive for thyroglobulin and thyroid transcription factor-1. They did not react against CD34. Ki-67 (MIB-1) labeling indexes were less than 1%. We thought that the spindle cells are derived from follicular cell and non-neoplastic, and it is important to recognize this lesion to distinguish from aggressive and lethal components seen in papillary carcinoma or anaplastic carcinoma.

Uterine cervical carcinosarcoma with heterologous mesenchymal component: a case report and review of the literature.

INTRODUCTION: Carcinosarcomas of the uterine cervix are very rare. Most of them have a homologous mesenchymal component, and cervical carcinosarcomas with a heterologous mesenchymal component are limited to nine cases. CASE REPORT: A 61-year-old Japanese woman was admitted to the hospital for treatment of a ureteral stone. Imaging studies detected an indistinct cervical mass. A histopathological diagnosis of the cervical biopsy was a carcinosarcoma. A total abdominal hysterectomy with bilateral salpingo-oophorectomy and pelvic lymphadenectomy was carried out upon a diagnosis of stage Ib1 cervical carcinosarcoma. Microscopically, the cervical mass revealed a carcinosarcoma consisting of endometrioid adenocarcinoma and chondrosarcoma. Immunohistochemically, p53 was positive in the epithelial and mesenchymal components. Postoperatively, the patient underwent radiation and chemotherapy. She is alive with no evidence of recurrence 5 years and 10 months after the operation. CONCLUSION: We suppose that the similar proportion of p53 overexpression in both the epithelial and mesenchymal components may be one of the findings explaining the histogenesis of this tumor by combination theory.

Familial Pancreatic Cancer at Elderly Siblings in Japan.

Two female siblings aged 87 and 90 years were clinically diagnosed as pancreatic cancer by abdominal ultrasonography and abdominal contrast-enhanced CT. Pancreatic cancer of these patients was confirmed during the autopsy. Both patients shared risk factors of pancreatic cancer; old age, diabetes, and passive smoking. Strong family history of pancreatic cancer was found in these two patients as their father and younger brother were also suffering from this cancer. The present study seems to report two eldest cases of familial pancreatic cancer in siblings. How to cite this article: Kashimoto Y, Onji M, et al. Familial Pancreatic Cancer at Elderly Siblings in Japan. Euroasian J Hepatogastroenterol 2019;9(1):52-54.

Crystallization and preliminary X-ray analysis of the catalytic domain of chitinase D from Bacillus circulans WL-12.

We report here on crystallization and preliminary X-ray analysis of the catalytic domain of chitinase D from Bacillus circulans WL-12. The native crystals of this domain were found to belong to the orthorhombic space group P2(1)2(1)2(1). To elucidate the structure of the catalytic domain by the multiple isomorphous replacement method, 30 kinds of derivatized crystals were prepared by soaking the native crystals into a mother liquor containing salts of heavy metal atoms. Difference Patterson maps calculated for four derivatives showed strong peaks in the Harker sections.

Pancreatic congestion in liver cirrhosis correlates with impaired insulin secretion.

BACKGROUND: Although impaired glucose tolerance is common in cirrhosis, this condition's pathogenesis remains undefined. This study aimed to clarify pathogenesis related to the pancreas in cirrhotic patients, and to evaluate associations between insulin secretion and pancreatic congestion due to portal hypertension. METHODS: Pancreatic perfusion parameters were analyzed by dynamic contrast-enhanced ultrasound (CE-US) in 41 patients (20 cirrhotic, 21 non-cirrhotic; age, 67.9 ± 13.3; female, 19), and prospectively compared to delta C-peptide immunoreactivity (ΔCPR). In a separate study, a retrospective chart review with human autopsy specimens was conducted, and vessels and islets of the pancreas were analyzed in 43 patients (20 cirrhotic, 23 controls; age, 71.5 ± 11.6; female, 15). RESULTS: In the CE-US study, the clinical characteristics indicative of portal hypertension (e.g., ascites and varices) had significantly higher incidences in the cirrhotic group than in the control group. Pancreatic drainage times were greater in the cirrhotic group (p < 0.0001), and had a significant negative correlation with ΔCPR (R = 0.42, p = 0.0069). In the histopathological study, the islets were enlarged in the cirrhotic group (p < 0.0001). However, the percentage of insulin-positive area per islet was decreased in the cirrhotic group (p < 0.0001), and had a significant negative correlation with the wall thickness of the pancreatic vein (R = 0.63, p < 0.0001). CONCLUSIONS: Pancreatic congestion was present in cirrhotic patients. Moreover, pancreatic congestion and insulin secretion were significantly correlated. This pathogenesis could be a key factor underlying the development of hepatogenous diabetes in cirrhotic patients.

Visual assessment of Ki67 using a 5-grade scale (Eye-5) is easy and practical to classify breast cancer subtypes with high reproducibility.

AIMS: Personalised breast cancer therapy requires pathological characterisation of tumours. The proliferative index, based on Ki67, is pivotal, but a standard method has not been established. Here we look for an easy and practical way to evaluate Ki67. METHODS: Immunohistochemical staining of estrogen receptors, progesterone receptors, HER2 and Ki67 (MIB-1) was performed on resected specimens from 406 primary invasive ductal carcinomas. Ki67 labelling index (LI) from manual counting was compared with visual assessment using a 5-grade scale (Eye-5). Next, 10 pathologists evaluated 100 samples with marked hot spots by using Eye-5. Another 100 samples without marking were also assessed by eight pathologists. One year later, two pathologists reviewed 222 cases with Eye-5. Prognosis was analysed among estrogen receptor-positive cases with postoperative endocrine therapy. RESULTS: Eye-5 showed good correlation to LI. All 136 cases of score 4-5 had LI >20% and all 56 cases of score 1 had LI<20%, which means that manual counting was not necessary for about half of the cases. Interobserver and intraobserver variability was low even when a hot spot was not fixed. Eye-5 also correlated with histological grade and lymph node metastasis. Combining Eye-5 and histological grade created a new algorism to predict LI, which allows 80% of all cases (74% of luminal cases) without manual counting. Cases of Eye-5 score 1-2 had significantly better survival than score 3-5. CONCLUSIONS: Visual assessment of Ki67 by a 5-grade scale (Eye-5) is fast, easy, and reliable with acceptably low interobserver and intraobserver variability. Eye-5 can replace LI in many luminal tumours, and is a strong candidate as a standard method of evaluating Ki67.

Cytopathologic characteristics and differential diagnostic considerations of osteolytic myxopapillary ependymoma.

Myxopapillary ependymoma (MPE) is a rare variant of conventional ependymoma found predominantly in the sacrococcygeal region in young adults and characterized by its distinct epithelial and stromal components (WHO grade I designation). MPE with extensive osteolysis is extremely uncommon and only up to 40 cases have been documented. A case is presented here in which imprint smears of a sacral tumor in an 18-year-old man revealed complex papillary structures, small loose clusters, or cord-like structures of bland tumor cells embedded in a myxoid or mucinous background. The tumor cells possessed uniformly round nuclei with a smooth nuclear outline, fine granular chromatin, and small nucleoli. Slender cytoplasmic fibrillary processes and occasional intracytoplasmic vacuoles were observed. A cytologic diagnosis of a MPE was suggested and histochemical and immunohistochemical studies were conducted on formalin-fixed, paraffin-embedded material. Immunohistochemically, the tumor cells showed diffuse and strong membranous and cytoplasmic staining for cytokeratin AE1/AE3, glial fibrillary protein, and S-100 protein, but negative for epithelial membrane antigen, pan-neuroendocrine markers (i.e., NSE, chromogranin A, synaptophysin), or brachyury. The proliferative index with MIB-1 was around 10%. The diagnosis of osteolytic MPE was confirmed based on cytopathologic, histopathological, immunohistochemical results, radiologic findings, and the location of the tumor. We demonstrated here the cytopathological features of osteolytic MPE with emphasis on differential diagnostic considerations.

Cytopathologic findings and differential diagnostic considerations of primary clear cell carcinoma of the lung.

Primary clear cell carcinoma (CLCC) of the lung is an extremely rare disease and is a subtype of large cell carcinoma, according to the World Health Organization (WHO) classification. A case is presented here in which intraoperative squash smears in a 53-year-old man revealed sheet and small clusters or tumor cells with prominent nucleoli and fine granular chromatin. Abundant translucent cytoplasm with occasional cytoplasmic vacuoles and intracytoplasmic eosinophilic inclusions was also identified. A cytopathologic diagnosis of a CLCC was suggested. Further evaluation and immunohistochemical studies were conducted on formalin-fixed, paraffin-embedded material. Nests of slightly acidophilic clear tumor cells with a prominent cellular membrane and an alveolar growth pattern were identified on H&E sections. Immunohistochemically, the tumor cells showed diffuse and strong membranous staining for CK(AE1/AE3), CK7, and CA19-9 but were negative for Napsin A, CK20, CDX2, TTF-1, alpha-fetoprotein, chromogranin A, synaptophysin, CD10, and CD56. The diagnosis of primary CLCC of the lung was confirmed based on cytopathologic, histopathologic, immunohistochemical results, and a detailed systemic examination to exclude a possible extrapulmonary origin. We report here the cytopathological features of CLCC of the lung with an emphasis on differential diagnostic considerations.

Cytopathologic characteristics of the primary strumal carcinoid tumor of the ovary: a case report with emphasis on differential diagnostic considerations.

Primary strumal carcinoid tumor of the ovary (SCTO) is an extremely rare entity, though the survival rate is excellent if the disease is confined to one ovary. A case is presented here in which intraoperative squash smears in a 45-year-old woman with a left adnexal mass revealed dispersed or small clusters of neoplastic cells forming loosely cohesive gland-like structures with abundant cytoplasm. The nuclear chromatin was finely granular with a "salt and pepper" appearance and occasional tiny nucleoli. The position of the nucleus presented a vaguely plasmacytoid appearance. Small fragments of thyroidal colloid-like structures were also identified. A cytopathologic diagnosis of a SCTO was suggested. Further evaluation and immunohistochemical studies were conducted on formalin-fixed, paraffin-embedded material. Cords or nests of uniform cells with abundant cytoplasm, and eccentric nuclei with coarse chromatin and occasional colloidal tissue were identified on H&E sections. The tumor cells showed diffuse and strong cytoplasmic staining for chromogranin A, synaptophysin, CD56, and vimentin but were negative for calretinin, α-inhibin or CDX2. The proliferative index with MIB-1 was around 3%. Thyroidal colloid-like structures were immunoreactive for thyroglobulin and TTF-1 stains. The diagnosis of primary SCTO was confirmed based on cytopathologic, histopathological, and immunohistochemical results, and the location of the tumor. Awareness of the cytopathological findings of SCTO can assist in diagnosing this rare entity correctly.

Cytopathologic features and differential diagnostic considerations of primary lymphoepithelioma-like carcinoma of the lung.

Primary lymphoepithelioma-like carcinoma (LELC) of the lung is an extremely rare disease that occurs more commonly in Asians, and is composed of undifferentiated carcinoma with prominent lymphoid stroma. LELC is reported to be closely associated with Epstein-Barr virus (EBV) infection. A case is presented here in which bronchial brushing smears in a 70-year-old man, revealed large clusters of neoplastic cells with scant cytoplasm. The nuclei were large, hyperchromatic, of irregular contour and with prominent nucleoli. Also identified were prominent intratumoral lymphoid infiltration and brisk mitotic figures. We detected EBV-coded small RNA in situ hybridization in smears. A cytologic diagnosis of a LELC was suggested. Further evaluation and immunohistochemical studies were conducted on formalin-fixed, paraffin-embedded material. Cords or nests of large neoplastic cells with enlarged nuclei and prominent nucleoli with marked lymphoid infiltration and lymphoid stroma were identified on H&E sections. Immunohistochemically, the tumor cells showed diffuse and strong membranous staining for CK(AE1/AE3), CK5/6, CK34ßE12, Napsin A and Bcl-2 but were negative for CK7, CK14, CK20, EMA, TTF-1, chromogranin A, synaptophysin and CD56. The proliferative index with MIB-1 was around 60%, and the p53 positive cells around 20%. The diagnosis of primary LELC of the lung was confirmed based on cytopathologic, histopathologic, immunohistochemical and EBER results, and a detailed systemic examination to exclude possible extrapulmonary (nasopharyngeal) origin. We report the cytopathological features of LELC of the lung and demonstrate here for the first time the positivity of the EBER with RNA-ISH method in smears with emphasis on differential diagnostic considerations.

Utility of immediate cytologic diagnosis of lung masses using ultrafast Papanicolaou stain.

PURPOSE: At Kagawa University Hospital we conduct immediate cytology using ultrafast Papanicolaou (U-Pap) stain when collecting cytology specimens by bronchoscopy or CT-guided needle aspiration, and report here an investigation of its utility. METHODS: The subjects were 503 patients for whom a final histopathological diagnosis could be made, taken from among 568 immediate cytology patients between July 2000 and June 2008. In immediate cytology at our hospital, a cytotechnologist goes to the bronchoscopy room just before tissue is collected. U-Pap stain is done immediately and examined microscopically. A tentative report is made orally on the spot as to the specimen adequacy, whether it is benign or malignant, and the presumed histopathological type. RESULTS: Of the 503 patients, the sample was inadequate in only two cases and there were no false positives. With respect to diagnostic accuracy, sensitivity was 82.9%, specificity was 100%, and the correct diagnosis rate was 85.6%. For lesions ≤3 cm, sensitivity was 77.2%, specificity was 100%, and the correct diagnosis rate was 81.3%, and for lesions ≤2 cm sensitivity was 74.7%, specificity was 100%, and the correct diagnosis rate was 81.3%. Diagnostic accuracy was thus maintained even for small lesions. No false positive case was detected. CONCLUSION: Because immediate cytology enables more precise sample collection, it is thought to be a useful technique that leads to improved diagnostic accuracy, while also improving the technical skill of the doctor collecting samples through immediate feedback.

Cytopathologic characteristics and differential diagnostic considerations of neuroglial heterotopia of the retropharyngeal space.

Neuroglial heterotopias (NGH) are rare congenital head and neck lesions composed of differentiated neuroectodermal tissue and representing developmental heterotopias rather than true neoplasms. The case of a male neonate with respiratory distress and early feeding problems depicting a retropharyngeal space mass which in the intraoperative squash smears revealed glial cells with multiple cytoplasmic processes is reported here. Small clusters of cuboidal epithelial cells with rosette-like ependymal structures and cuboidal cells arranged in sheets or branching folds suggestive of choroid plexus cells were also identified. Through this cytological approach a cytologic diagnosis of a NGH or low-grade astrocytoma was suggested. Further evaluation and immunohistochemical studies were conducted on formalin-fixed, paraffin-embedded material. Glial cells, ependymal structures and choroid plexus were identified on H&E sections. Immunohistochemically, the glial cells showed diffuse and strong cytoplasmic staining for glial fibrillary acidic protein (GFAP) and S-100 protein and focal immunoreactivity for synaptophysin and neurofilament. The proliferative index with MIB-1 was around 4%. The diagnosis of NGH of the retropharyngeal space was confirmed based on the clinical, cytopathologic, histopathology, immunohistochemical results, and the location of the tumor. We demonstrated here for the first time the cytopathological features of NGH of the retropharyngeal space with emphasis on differential diagnostic considerations.

Epidermoid cyst in an intrapancreatic accessory spleen: three case reports and review of the literatures.

The development of an epidermoid cyst in an intrapancreatic accessory spleen is an extremely rare lesion, with only 17 cases being reported in the English literature. All such cases were located in the pancreatic tail, some of which showed carbohydrate antigen 19-9 (CA19-9) immunoreactivity in the lining of the epithelium. A few of them indicated an elevation of the serum CA19-9 level. Here we report three cases of an epidermoid cyst in an intrapancreatic accessory spleen. Cases 1 and 2 were 57-year-old and 70-year-old women, while case 3 was a 37-year-old man. All three cases were asymptomatic. Serum CA19-9 levels showed within normal limits (case 1), slightly elevated (case 2), and clearly elevated (case 3). They underwent a distal pancreatectomy with splenectomy (cases 1 and 2) and without splenectomy (case 3). Grossly, the surgical specimen was a well-demarcated, multiple (case 1) or solitary (cases 2 and 3) cystic mass in the pancreatic tail. A high level of fluid CA 19-9 was detected in case 1. Microscopically, the cystic walls were lined with squamous and cuboidal epithelium, which were surrounded by normal splenic tissue and hyalinized fibrous tissue. The lining squamous epithelium was revealed as nonkeratinizing (Cases 1 and 2) or keratinizing (Case 3). Immunohistochemically, CA19-9 was positive in the monolayer and surface layer of the cuboidal epithelium, but negative for the keratinizing squamous epithelium. As for the histogenesis, it is suggested that the cystic lining of the epithelium may derive from the pancreatic duct which protrudes into the accessory spleen.

Cytopathological features of warty (condylomatous) carcinoma of the penis: a case report and distinction from other verruciform penile tumors.

Warty (condylomatous) carcinoma (WC) is a rare specific variant of invasive squamous cell carcinoma that shows hybrid features of condyloma with invasive cell carcinoma. As compared with conventional squamous cell carcinoma, WC tends to run a less aggressive clinical course. A case is presented here in which squash smears of a penile foreskin tumor in a 65-year-old male revealed small cohesive clusters and sheets of tumor cells in papillary configurations. The neoplastic cells were polygonal to elongated and contained oval nuclei, coarse chromatin pattern, and distinct nucleoli. Nuclear pleomorphism and loss of nuclear polarity were observed. Characteristically, there were also many koilocytes demonstrating mild to moderate nuclear atypia and perinuclear cytoplasmic halos. A cytologic diagnosis of a verruciform penile tumor was suggested. Histologic examination of the tumor showed a hyper-parakeratotic arborizing papillomatous growth with thin fibrovascular cores and the tips were variably rounded or tapered. Obvious koilocytic cytopathic change, nuclear pleomorphism, and focal stromal invasion were observed. Immunohistochemically, the tumor cells showed diffuse and strong membranous staining for cytokeratin (AE1/AE3) while the MIB-1 and p53 immunoreactive cells were confined to the basal areas of the papillae. No lymphovascular invasion was detected in D2-40 or elastic Van-Gieson stains. On the basis of the overall features, we confirmed a final diagnosis of penile WC. We demonstrated here for the first time the cytopathological features of penile WC with emphasis on differential diagnostic considerations.

Cytological findings of mixed squamous cell and glandular papilloma in the lung.

Pulmonary mixed squamous cell and glandular papilloma is an extremely rare neoplasm. This is the first cytological report of such a rare neoplasm. A 59-year-old Japanese man was admitted to the hospital complaining of a persistent cough and bloody sputum. A bronchial endoscopic examination revealed an endobronchial polypoid tumor. Upon bronchial brush cytology by Papanicolaou stain, squamous dysplasia showing mild atypia was suspected. The smears showed moderate cellularity with singly scattered cells or loose clusters of cells, consisting of squamous cells and a few columnar cells. Nuclei of the squamous cells showed mild atypia, but there was no nuclear atypia of the columnar cells. Upon intraoperative pathological examination by frozen section, pulmonary mixed squamous cell and glandular papilloma was suspected. Intraoperative imprint cytology by Ultrafast Papanicolaou stain showed a few differences in comparison with bronchial brush cytology, which were thought to be due to differences in obtaining cytological specimens or the steps prior to the staining. The patient underwent a segmentectomy of the left lung. Histopathological diagnosis confirmed a mixed squamous cell and glandular papilloma. The postoperative course has been uneventful for 5 years after surgery. It was thought that cytology was diagnostically inadequate on its own in the present case. However, mixed squamous cell and glandular papilloma must be considered as another type of pulmonary tumor in cytological preparations, especially in a case showing endobronchial papillary growth by bronchoscopy.

Cytopathologic features of orbital intraosseous chordoid meningioma: report of a case and distinction from other myxoid/mucoid tumors.

Chordoid meningioma (CM) is characterized by a striking histologic resemblance to chordoma and propensity for aggressive behavior or recurrence (WHO grade II designation). Orbital intraosseous CM is extremely uncommon and only one case report has been documented. A case is presented here in which squash smears of a left orbital tumor in a 53-year-old male revealed small clusters or cord-like structures of bland tumor cells embedded in a myxoid or mucinous background. Whorl-like structures were also identified. The tumor cells possessed uniformly round nuclei with a smooth nuclear outline, fine granular chromatin, and small nucleoli. Occasional intranuclear inclusions, coarse collageneous cytoplasmic filaments were observed. Many spindle-shaped cells with similar nuclear findings were also seen. A cytologic diagnosis of a chordoid meningioma was suggested and histochemical and immunohistochemical studies were conducted on formalin-fixed, paraffin-embedded material. Immunohistochemically, the tumor cells showed diffuse and strong membranous and cytoplasmic staining for vimentin, epithelial membrane antigen (EMA) and faintly reactive with S-100 protein but negative for pan-neuroendocrine markers (i.e., NSE, chromogranin A, synaptophysin), cytokeratin AE1/AE3, smooth muscle actin, D2-40, brachyury or class III beta-tubulin. The proliferative index with MIB-1 was less than 1%. The diagnosis of orbital intraosseous CM was confirmed based on cytopathologic, histopathological, immunohistochemical results, location of the tumor, and the lack connection to the duramater. We demonstrated here for the first time the cytopathological features of intraosseous CM with emphasis on differential diagnostic considerations.