Current status of cytopathology practices in Korea: annual report on the Continuous Quality Improvement program of the Korean Society for Cytopathology for 2018

The Korean Society for Cytopathology has conducted the Continuous Quality Improvement program for cytopathology laboratories in Korea since 1995. In 2018 as part of the program, an annual survey of cytologic data was administered to determine the current status of cytopathology practices in Korea. Methods: A questionnaire was administered to 211 cytopathology laboratories. Individual laboratories submitted their annual statistics regarding cytopathology practices, diagnoses of gynecologic samples, inadequacy rates, and gynecologic cytology-histology correlation review (CHCR) data for 2018. In addition, proficiency tests and sample adequacy assessments were conducted using five consequent gynecologic slides. Results: Over 10 million cytologic exams were performed in 2018, and this number has almost tripled since this survey was first conducted in 2004 (compounded annual growth rate of 7.2%). The number of non-gynecologic samples has increased gradually over time and comprised 24% of all exams. The overall unsatisfactory rate was 0.14%. The ratio of the cases with atypical squamous cells to squamous intraepithelial lesions accounted for up to 4.24. The major discrepancy rate of the CHCR in gynecologic samples was 0.52%. In the proficiency test, the major discrepancy rate was approximately 1%. In the sample adequacy assessment, a discrepancy was observed in 0.1% of cases. Conclusions: This study represents the current status of cytopathology practices in Korea, illustrating the importance of the Continuous Quality Improvement program for increasing the accuracy and credibility of cytopathologic exams as well as developing national cancer exam guidelines and government projects on the prevention and treatment of cancer.

Analysis of PAX8 immunohistochemistry in lung cancers: a meta-analysis

Background@#In this meta-analysis, we aimed to evaluate the PAX8 immunohistochemical expressions in primary lung cancers and metastatic cancers to the lung. @*Methods@#We identified and reviewed relevant articles from the PubMed databases. Ultimately, 18 articles were included in this meta-analysis. PAX8 expression rates were analyzed and compared between primary and metastatic lung cancers. @*Results@#The PAX8 expression rate in primary lung cancers was 0.042 (95% confidence interval [CI], 0.025 to 0.071). PAX8 expression rates of small cell (0.129; 95% CI, 0.022 to 0.496) and non-small cell carcinomas of the lung (0.037; 95% CI, 0.022 to 0.061) were significantly different (p=.049 in a meta-regression test). However, the PAX8 expression rates of adenocarcinoma (0.013; 95% CI, 0.006 to 0.031) and squamous cell carcinoma (0.040; 95% CI, 0.016 to 0.097) were not significantly different. PAX8 expression rates of metastatic carcinomas to the lung varied, ranging from 1.8% to 94.9%. Metastatic carcinomas from the lung to other organs had a PAX8 expression rate of 6.3%. The PAX8 expression rates of metastatic carcinomas from the female genital organs, kidneys, and thyroid gland to the lung were higher than those of other metastatic carcinomas. @*Conclusions@#Primary lung cancers had a low PAX8 expression rate regardless of tumor subtype. However, the PAX8 expression rates of metastatic carcinomas from the female genital organs, kidneys, and thyroid were significantly higher than those of primary lung cancers.

Diagnostic Test Accuracy Review of Cytology for Squamous Intraepithelial Lesion and Squamous Cell Carcinoma of Uterine Cervix

BACKGROUND: Even though cervico-vaginal smears have been used as a primary screening test for cervical carcinoma, the diagnostic accuracy has been controversial. The present study aimed to evaluate the diagnostic accuracy of cytology for squamous intraepithelial lesion (SIL) and squamous cell carcinoma (SqCC) of the uterine cervix through a diagnostic test accuracy (DTA) review. METHODS: A DTA review was performed using 38 eligible studies that showed concordance between cytology and histology. In the DTA review, sensitivity, specificity, diagnostic odds ratio (OR), and the area under the curve (AUC) on the summary receiver operating characteristic (SROC) curve were calculated. RESULTS: In the comparison between abnormal cytology and histology, the pooled sensitivity and specificity were 93.9% (95% confidence interval [CI], 93.7%–94.1%) and 77.6% (95% CI, 77.4–77.8%), respectively. The diagnostic OR and AUC on the SROC curve were 8.90 (95% CI, 5.57–14.23) and 0.8148, respectively. High-grade squamous intraepithelial lesion (HSIL) cytology had a higher sensitivity (97.6%; 95% CI, 94.7%–97.8%) for predicting HSIL or worse histology. In the comparison between SqCC identified on cytology and on histological analysis, the pooled sensitivity and specificity, diagnostic OR, and AUC were 92.7% (95% CI, 87.3%–96.3%), 87.5% (95% CI, 87.2%–87.8%), 865.81 (95% CI, 68.61–10,925.12), and 0.9855, respectively. Geographic locations with well-organized screening programs had higher sensitivity than areas with insufficient screening programs. CONCLUSION: These results indicate that cytology had a higher sensitivity and specificity for detecting SIL and SqCC of the uterine cervix during primary screening.

Response to Comment on “Prognostic Role of Claudin-1 Immunohistochemistry in Malignant Solid Tumors: A Meta-Analysis”

No abstract available.

Prognostic Accuracy of Massive Transfusion, Critical Administration Threshold, and Resuscitation Intensity in Assessing Mortality in Traumatic Patients with Severe Hemorrhage: a Meta-Analysis

Prognostic Role of Claudin-1 Immunohistochemistry in Malignant Solid Tumors: A Meta-Analysis

BACKGROUND: Although the correlation between low claudin-1 expression and worse prognosis has been reported, details on the prognostic implications of claudin-1 expression in various malignant tumors remain unclear. The present study aimed to elucidate the prognostic roles of claudin- 1 immunohistochemistry (IHC) in various malignant tumors through a meta-analysis. METHODS: The study included 2,792 patients from 22 eligible studies for assessment of the correlation between claudin-1 expression and survival rate in various malignant tumors. A subgroup analysis based on the specific tumor and evaluation criteria of claudin-1 IHC was conducted. RESULTS: Low claudin-1 expression was significantly correlated with worse overall survival (OS) (hazard ratio [HR], 1.851; 95% confidence interval [CI], 1.506 to 2.274) and disease-free survival (DFS) (HR, 2.028; 95% CI, 1.313 to 3.134) compared to high claudin-1 expression. Breast, colorectal, esophageal, gallbladder, head and neck, and lung cancers, but not cervical, liver or stomach cancers, were significantly correlated with worse OS. Breast, colorectal, esophageal, and thyroid cancers with low claudin-1 expression were associated with poorer DFS. In the lower cut-off subgroup (< 25.0%) with respect to claudin-1 IHC, low claudin-1 expression was significantly correlated with worse OS and DFS. CONCLUSIONS: Taken together, low claudin-1 IHC expression is significantly correlated with worse survival in various malignant tumors. More detailed criteria for claudin-1 IHC expression in various malignant tumors are needed for application in daily practice.

FOXO1 Suppression is a Determinant of Acquired Lapatinib-Resistance in HER2-Positive Gastric Cancer Cells Through MET Upregulation / Journal of the Korean Cancer Association, 대한암학회지

PURPOSE: Lapatinib is a candidate drug for treatment of trastuzumab-resistant, human epidermal growth factor receptor 2 (HER2)–positive gastric cancer (GC). Unfortunately, lapatinib resistance renders this drug ineffective. The present study investigated the implication of forkhead box O1 (FOXO1) signaling in the acquired lapatinib resistance in HER2-positive GC cells. MATERIALS AND METHODS: Lapatinib-resistant GC cell lines (SNU-216 LR2-8) were generated in vitro by chronic exposure of lapatinib-sensitive, HER2-positive SNU-216 cells to lapatinib. SNU-216 LR cells with FOXO1 overexpression were generated by stable transfection of a constitutively active FOXO1 mutant (FOXO1A3). HER2 and MET in SNU-216 LR cells were downregulated using RNA interference. The sensitivity of GC cells to lapatinib and/or cisplatin was determined by crystal violet assay. In addition, Western blot analysis, luciferase reporter assay and reverse transcription–polymerase chain reaction were performed. RESULTS: SNU-216 LR cells showed upregulations of HER2 and MET, but downregulation of FOXO1 compared to parental SNU-216 cells. FOXO1 overexpression in SNU-216 LR cells significantly suppressed resistance to lapatinib and/or cisplatin. In addition, FOXO1 negatively controlled HER2 and MET at the transcriptional level and was negatively controlled by these molecules at the post-transcriptional level. A positive crosstalk was shown between HER2 and MET, each of which increased resistance to lapatinib and/or cisplatin. CONCLUSION: FOXO1 serves as an important linker between HER2 and MET signaling pathways through negative crosstalks and is a key regulator of the acquired lapatinib resistance in HER2-positive GC cells. These findings provide a rationale for establishing a novel treatment strategy to overcome lapatinib resistance in a subtype of GC patients.

Prognostic Role of Metastatic Lymph Node Ratio in Papillary Thyroid Carcinoma

BACKGROUND: The aim of this study is to elucidate the clinicopathological significances, including the prognostic role, of metastatic lymph node ratio (mLNR) and tumor deposit diameter in papillary thyroid carcinoma (PTC) through a retrospective review and meta-analysis. METHODS: We categorized the cases into high (≥ 0.44) and low mLNR (< 0.44) and investigated the correlations with clinicopathological parameters in 64 PTCs with neck level VI lymph node (LN) metastasis. In addition, meta-analysis of seven eligible studies was used to investigate the correlation between mLNR and survival. RESULTS: Among 64 PTCs with neck level VI LN metastasis, high mLNR was found in 34 PTCs (53.1%). High mLNR was significantly correlated with macrometastasis (tumor deposit diameter ≥ 0.2 cm), extracapsular spread, and number of metastatic LNs. Based on linear regression test, mLNR was significantly increased by the largest LN size but not the largest metastatic LN (mLN) size. High mLNR was not correlated with nuclear factor κB or cyclin D1 immunohistochemical expression, Ki-67 labeling index, or other pathological parameters of primary tumor. Based on meta-analysis, high mLNR significantly correlated with worse disease-free survival at the 5-year and 10-year follow-up (hazard ratio [HR], 4.866; 95% confidence interval [CI], 3.527 to 6.714 and HR, 5.769; 95% CI, 2.951 to 11.275, respectively). CONCLUSIONS: Our data showed that high mLNR significantly correlated with worse survival, macrometastasis, and extracapsular spread of mLNs. Further cumulative studies for more detailed criteria of mLNR are needed before application in daily practice.

Eccrine Spiradenoma of the Scalp

Eccrine spiradenoma is an uncommon benign adnexal tumor originating from the eccrine sweat gland. We diagnosed a eccrine spiradenoma on a 55-year-old man with histopathologic confirmation upon biopsy followed by complete resection, who had visited our clinic with a chief complain of occipital scalp mass. The solitary eccrine spiradenoma occurring in the scalp is rarely to be seen and should be considered as a differential diagnosis for a solitary cystic mass of the scalp.

Clinicopathological Significance and Diagnostic Accuracy of c-MET Expression by Immunohistochemistry in Gastric Cancer: A Meta-Analysis

PURPOSE: The aim of the present study was to elucidate the clinicopathological significance and diagnostic accuracy of immunohistochemistry (IHC) for determining the mesenchymal epidermal transition (c-MET) expression in patients with gastric cancer (GC). MATERIALS AND METHODS: The present meta-analysis investigated the correlation between c-MET expression as determined by IHC and the clinicopathological parameters in 8,395 GC patients from 37 studies that satisfied the eligibility criteria. In addition, a concordance analysis was performed between c-MET expression as determined by IHC and c-MET amplification, and the diagnostic test accuracy was reviewed. RESULTS: The estimated rate of c-MET overexpression was 0.403 (95% confidence interval [CI], 0.327~0.484) and it was significantly correlated with male patients, poor differentiation, lymph node metastasis, higher TNM stage, and human epidermal growth factor receptor 2 (HER2) positivity in IHC analysis. There was a significant correlation between c-MET expression and worse overall survival rate (hazard ratio, 1.588; 95% CI, 1.266~1.992). The concordance rates between c-MET expression and c-MET amplification were 0.967 (95% CI, 0.916~0.987) and 0.270 (95% CI, 0.173~0.395) for cases with non-overexpressed and overexpressed c-MET, respectively. In the diagnostic test accuracy review, the pooled sensitivity and specificity were 0.56 (95% CI, 0.50~0.63) and 0.79 (95% CI, 0.77~0.81), respectively. CONCLUSIONS: The c-MET overexpression as determined by IHC was significantly correlated with aggressive tumor behavior and positive IHC status for HER2 in patients with GC. In addition, the c-MET expression status could be useful in the screening of c-MET amplification in patients with GC.

Detection of Tumor Multifocality Is Important for Prediction of Tumor Recurrence in Papillary Thyroid Microcarcinoma: A Retrospective Study and Meta-Analysis

BACKGROUND: The clinicopathological characteristics and conclusive treatment modality for multifocal papillary thyroid microcarcinoma (mPTMC) have not been fully established. METHODS: A retrospective study, systematic review, and meta-analysis were conducted to elucidate the clinicopathological significance of mPTMC. We investigated the multiplicity of 383 classical papillary thyroid microcarcinomas (PTMCs) and the clinicopathological significance of incidental mPTMCs. Correlation between tumor recurrence and multifocality in PTMCs was evaluated through a systematic review and meta-analysis. RESULTS: Tumor multifocality was identified in 103 of 383 PTMCs (26.9%). On linear regression analysis, primary tumor diameter was significantly correlated with tumor number (R2=0.014, p=.021) and supplemental tumor diameter (R2=0.117, p=.023). Of 103 mPTMCs, 61 (59.2%) were non-incidental, with tumor detected on preoperative ultrasonography, and 42 (40.8%) were diagnosed (incidental mPTMCs) on pathological examination. Lymph node metastasis and higher tumor stage were significantly correlated with tumor multifocality. However, there was no difference in nodal metastasis or tumor stage between incidental and non-incidental mPTMCs. On meta-analysis, tumor multifocality was significantly correlated with tumor recurrence in PTMCs (odds ratio, 2.002; 95% confidence interval, 1.475 to 2.719, p<.001). CONCLUSIONS: Our results show that tumor multifocality in PTMC, regardless of manner of detection, is significantly correlated with aggressive tumor behavior.

Core Needle Biopsy Is a More Conclusive Follow-up Method Than Repeat Fine Needle Aspiration for Thyroid Nodules with Initially Inconclusive Results: A Systematic Review and Meta-Analysis

BACKGROUND: This study investigated the appropriate management of thyroid nodules with prior non-diagnostic or atypia of undetermined significance/follicular lesion of undetermined significance (AUS/FLUS) through a systematic review and meta-analysis. METHODS: This study included 4,235 thyroid nodules from 26 eligible studies. We investigated the conclusive rate of follow-up core needle biopsy (CNB) or repeat fine needle aspiration (rFNA) after initial fine needle aspiration (FNA) with non-diagnostic or AUS/FLUS results. A diagnostic test accuracy (DTA) review was performed to determine the diagnostic role of the follow-up CNB and to calculate the area under the curve (AUC) on the summary receiver operating characteristic (SROC) curve. RESULTS: The conclusive rates of follow-up CNB and rFNA after initial FNA were 0.879 (95% confidence interval [CI], 0.801 to 0.929) and 0.684 (95% CI, 0.627 to 0.736), respectively. In comparison of the odds ratios of CNB and rFNA, CNB had more frequent conclusive results than rFNA (odds ratio, 5.707; 95% CI, 2.530 to 12.875). Upon subgroup analysis, follow-up CNB showed a higher conclusive rate than rFNA in both initial non-diagnostic and AUS/FLUS subgroups. In DTA review of followup CNB, the pooled sensitivity and specificity were 0.94 (95% CI, 0.88 to 0.97) and 0.88 (95% CI, 0.84 to 0.91), respectively. The AUC for the SROC curve was 0.981, nearing 1. CONCLUSIONS: Our results show that CNB has a higher conclusive rate than rFNA when the initial FNA produced inconclusive results. Further prospective studies with more detailed criteria are necessary before follow-up CNB can be applied in daily practice.

Forkhead Transcription Factor FOXO1 Inhibits Angiogenesis in Gastric Cancer in Relation to SIRT1 / Journal of the Korean Cancer Association, 대한암학회지

PURPOSE: We previously reported that forkhead transcription factors of the O class 1 (FOXO1) expression in gastric cancer (GC) was associated with angiogenesis-related molecules. However, there is little experimental evidence for the direct role of FOXO1 in GC. In the present study, we investigated the effect of FOXO1 on the tumorigenesis and angiogenesis in GC and its relationship with SIRT1. MATERIALS AND METHODS: Stable GC cell lines (SNU-638 and SNU-601) infected with a lentivirus containing FOXO1 shRNA were established for animal studies as well as cell culture experiments. We used xenograft tumors in nude mice to evaluate the effect of FOXO1 silencing on tumor growth and angiogenesis. In addition, we examined the association between FOXO1 and SIRT1 by immunohistochemical tissue array analysis of 471 human GC specimens and Western blot analysis of xenografted tumor tissues. RESULTS: In cell culture, FOXO1 silencing enhanced hypoxia inducible factor-1alpha (HIF-1alpha) expression and GC cell growth under hypoxic conditions, but not under normoxic conditions. The xenograft study showed that FOXO1 downregulation enhanced tumor growth, microvessel areas, HIF-1alpha activation and vascular endothelial growth factor (VEGF) expression. In addition, inactivated FOXO1 expression was associated with SIRT1 expression in human GC tissues and xenograft tumor tissues. CONCLUSION: Our results indicate that FOXO1 inhibits GC growth and angiogenesis under hypoxic conditions via inactivation of the HIF-1alpha-VEGF pathway, possibly in association with SIRT1. Thus, development of treatment modalities aiming at this pathway might be useful for treating GC.

Total Surface Area Is Useful for Differentiating between Aggressive and Favorable Multifocal Papillary Thyroid Carcinomas

PURPOSE: The purpose of the present study was to identify more useful parameters for predicting behaviors of multifocal papillary thyroid carcinoma (PTC). MATERIALS AND METHODS: We investigated dominant tumor diameter (TD), total tumor diameter (TTD), and total surface area (TSA) in tumors from 588 patients and evaluated their usefulness as parameters for assessment of tumor behaviors in multifocal PTCs. RESULTS: In 588 PTCs, tumor multifocality was found in 179 PTCs (30.4%). Multifocal tumors were significantly associated with extrathyroidal extension, lymph node metastasis, and higher tumor stage grouping (p3.14 cm2 had higher rates of nodal metastasis than mPMCs with TSA 1.0 cm and with TTD 3.14 cm2 than in unifocal papillary thyroid microcarcinomas (uPMCs) (TD 1.0 cm) (p=0.244). CONCLUSION: Our results suggest that mPMCs with TSA >3.14 cm2 show more aggressive behavior than uPMCs and mPMCs with TSA < or =3.14 cm2. TSA could be useful in distinguishing aggressive mPMCs from favorable cases.

MUC2 Expression Is Correlated with Tumor Differentiation and Inhibits Tumor Invasion in Gastric Carcinomas: A Systematic Review and Meta-analysis

BACKGROUND: While MUC2 is expressed in intestinal metaplasia and malignant lesions, the clinicopathological significance of MUC2 expression is not fully elucidated in gastric carcinoma (GC). METHODS: The present study investigated the correlation between MUC2 expression and clinicopathological parameters in 167 human GCs. In addition, to confirm the clinicopathological significance of MUC2 expression, we performed a systematic review and meta-analysis in 1,832 GCs. RESULTS: MUC2 expression was found in 58 of 167 GCs (34.7%). MUC2-expressing GC showed lower primary tumor (T), regional lymph node (N), and tumor node metastasis (TNM) stages compared with GCs without MUC2 expression (p=.001, p=.001, and p=.011, respectively). However, MUC2 expression was not correlated with Lauren's classification and tumor differentiation. In meta-analysis, MUC2 expression was significantly correlated with differentiation and lower tumor stage (odds ratio [OR], 1.303; 95% confidence interval [CI], 1.020 to 1.664; p = .034 and OR, 1.352; 95% CI, 1.055 to 1.734; p = .017, respectively) but not with Lauren's classification, pN stage, or pTNM stage. CONCLUSIONS: MUC2 expression was correlated with a lower tumor depth and lower lymph node metastasis in our study; the meta-analysis showed a correlation of MUC2 expression with tumor differentiation and lower tumor depth.

Traumatic Bowel Perforation and Inguinal Hernia Masking a Mesenteric Calcifying Fibrous Tumor

No abstract available.

Availability of Preoperative Systemic Steroids on Endoscopic Sinus Surgery for Chronic Rhinosinusitis with Nasal Polyposis

PURPOSE: To analyze the outcome of endoscopic sinus surgery (ESS) after preoperative systemic steroid (PSS) treatment for chronic rhinosinusitis (CRS) with nasal polyposis (NP) and to investigate and compare clinicopathological factors associated with the outcome. MATERIALS AND METHODS: We performed a retrospective chart review of 468 patients with CRS with NP who underwent primary ESS between January 2005 and October 2011. 124 patients who met the inclusion criteria were included. Beginning from 2008, our clinic administered steroid preoperatively in patients of CRS with NP, thus there were 84 patients with preoperative systemic steroid (PSS group) and another 40 patients without such regimen (no PSS group). To evaluate the outcome after ESS, poor outcome and complication were analyzed according to the following parameters: age, sex, follow-up duration, eosinophilic infiltration, atopy, asthma, Lund-Mackay score, and polyp grade. RESULTS: There was no significant difference in poor outcome rates between the PSS and no PSS group (35.0% vs. 47.6%, p=0.185). There was no significant difference in complication rates between the PSS and no PSS group (10% vs. 6%, p=0.468). As with the multivariate analysis of the clincopathological factors to the poor outcome rate, presence of asthma and eosinophilic infiltration were significantly related (odds ratio as 6.555 and 4.505, respectively), whereas PSS was confirmed as less likely related (odds ratio 0.611). CONCLUSION: Low dose PSS administration does not seem to have an effect on the outcome after ESS in patients who have CRS with NP. Eosinophilic infiltration and presence of asthma are important predictors of surgical outcome.

A Case of Intra-Abdominal Kikuchi's Disease with Increased FDG Uptake on PET-CT that Mimicked Intra-Abdominal Lymphoma

Kikuchi's disease is a benign disease characterized mainly by fever and cervical lymphadenitis. We report a case of Kikuchi's disease that manifested as intra-abdominal lymphadenitis. A 39 year old woman presented with fever that had persisted for one week. Her history and physical examination were unremarkable. The laboratory findings revealed mild leukopenia and increased C-reactive protein. Abdominal CT revealed multiple lymph node enlargements in the mesenteric root and around the ileocecal valve. Positron emission tomography-computed tomography (PET-CT) revealed increased 18-fluoro-deoxyglucose(FDG) uptake in the lymph nodes observed by abdominal CT. A laparoscopic excisional biopsy of the lymph node was performed for a confirmatory diagnosis and the pathology findings were compatible with Kikuchi's disease. Although intra-abdominal Kikuchi's disease is a rare disease, it should be considered in a differential diagnosis of intra-abdominal lymphadenopathy with increased FDG uptake on PET-CT.

Extranodal Follicular Dendritic Cell Sarcoma with Rapid Growth in Parapharynx: A Case Report

Follicular dendritic cell sarcoma (FDCS) is a rare malignancy arising from the antigen-presenting cells in the lymph node and extranodal tissue. We describe a 31-year-old male patient who presented with a swelling of the left parapharynx. The radiologic findings showed a 4.7x4.5x1.9 cm-sized, ill-defined mass in the left parapharyngeal space. A fine-needle aspiration cytology was performed and it showed scattered, irregular, cohesive clusters of tumor cells with a spindle-to-ovoid shape with irregular contours in a background of lymphocytes. Based on these findings, a diagnosis of spindle cell neoplasm was made. The surgically resected tumor was composed of elongated, ovoid or polygonal cells showing positive immunohistochemistry for CD21, CD23, and CD35. Postoperatively, the residual tumor was observed to undergo a rapidly growth. There is an overlap in the cytologic and histologic findings between FDCS of the parapharynx and other tumors. Pathologists should therefore be aware of its characteristics not only to provide an accurate diagnosis but also to recommend the appropriate clinical management.

Extranodal Follicular Dendritic Cell Sarcoma with Rapid Growth in Parapharynx: A Case Report

Follicular dendritic cell sarcoma (FDCS) is a rare malignancy arising from the antigen-presenting cells in the lymph node and extranodal tissue. We describe a 31-year-old male patient who presented with a swelling of the left parapharynx. The radiologic findings showed a 4.7x4.5x1.9 cm-sized, ill-defined mass in the left parapharyngeal space. A fine-needle aspiration cytology was performed and it showed scattered, irregular, cohesive clusters of tumor cells with a spindle-to-ovoid shape with irregular contours in a background of lymphocytes. Based on these findings, a diagnosis of spindle cell neoplasm was made. The surgically resected tumor was composed of elongated, ovoid or polygonal cells showing positive immunohistochemistry for CD21, CD23, and CD35. Postoperatively, the residual tumor was observed to undergo a rapidly growth. There is an overlap in the cytologic and histologic findings between FDCS of the parapharynx and other tumors. Pathologists should therefore be aware of its characteristics not only to provide an accurate diagnosis but also to recommend the appropriate clinical management.