A prospective observational study on chemotherapy-induced nausea and vomiting (CINV) in patients with gynecologic cancer by the CINV Study Group of Japan.

OBJECTIVE: This study was performed to investigate the occurrence of and risk factors for chemotherapy-induced nausea and vomiting (CINV) in patients with gynecologic cancer. METHODS: In total, 214 patients with gynecologic cancer who underwent highly emetogenic (HEC) or moderately emetogenic chemotherapy (MEC) were evaluated. We investigated the relationship between CINV and clinical factors and the accuracy of estimation of CINV by medical staff in the acute and late phases. Vomiting was evaluated in terms of frequency, and nausea was evaluated with a 100-mm visual analog scale on days 1 to 7. We also analyzed the risk factors and changes in CINV over time using a generalized linear mixed (GLM) model. RESULTS: The multivariate analysis revealed no significant risk factors for acute CINV. The independent risk factors for delayed nausea were a morning sickness history (odds ratio [OR], 2.687; 95% confidence interval [95% CI], 1.450-4.976; p=0.0017), age (each 1-year increment) (OR, 0.97; 95% CI, 0.944-0.996; p=0.0235), and HEC (OR, 2.134; 95% CI, 1.039-4.383; p=0.0391). The GLM model demonstrated that the independent factors affecting nausea were significant morning sickness (p=0.0101) and HEC (p=0.0136). These data also showed more severe nausea from days 3 to 5, but the negative predictive value for estimation of delayed nausea by medical staff was 57.8%. CONCLUSION: Our data suggest that improvement of preventive antiemetic administration is needed for patients with risk factors to manage delayed CINV caused by HEC and by MEC.

Prospective evaluation of the Amplicor HPV test for predicting progression of cervical intraepithelial neoplasia 2.

AIM: The aim of this study was to evaluate the clinical performance of the Amplicor HPV test, which detects 13 high-risk human papillomaviruses (HR-HPV), and to determine the association between consistent HR-HPV infection and progression of cervical intraepithelial neoplasia (CIN) 2 to CIN3. MATERIAL AND METHODS: This multi-institutional prospective study enrolled 122 women diagnosed with CIN2 by central pathological review. Subjects were tested at study entry and every 6 months over a 24-month period by cytology, Amplicor HPV test and colposcopy. Central pathological review was performed at the end of the study or if CIN progression was suspected. RESULTS: Ninety-three of the 122 participants completed all tests in the study and were included in the analysis. HR-HPV was detected in 87/93 (93.5%) participants at study entry. Twenty-four of the 87 HR-HPV-positive participants progressed to ≥CIN3, compared with none of the six participants who were HR-HPV-negative at study entry. The positive predictive value, negative predictive value, sensitivity and specificity of the Amplicor HPV test at study entry for predicting ≥CIN3 progression were 27.6%, 100%, 100% and 8.7%, respectively. Sixty-two participants were HR-HPV-positive from study entry through to study completion, 24 of whom progressed to ≥CIN3. None of 31 participants without continuous HR-HPV detection progressed to ≥CIN3. For continuous HR-HPV detection, the positive predictive value, negative predictive value, sensitivity and specificity of the Amplicor HPV test were 38.7%, 100%, 100% and 44.9%, respectively. CONCLUSIONS: All participants who progressed to ≥CIN3 were continuously HR-HPV-positive. The Amplicor HPV test thus demonstrated a good performance for predicting CIN3 progression.

Clinical management of atypical polypoid adenomyoma of the uterus. A clinicopathological review of 29 cases.

OBJECTIVE: The clinical management of atypical polypoid adenomyoma (APAM) of the uterus remains to be established. We collected APAM cases, reviewed the clinicopathological features, and discussed the clinical management. METHODS: Twenty-nine patients with APAM were identified by searching the tumor registry of the Japan Clinical Oncology Group (JCOG). Clinical information and histological specimens were obtained from 13 institutional members of the JCOG, and a central pathological review was performed. RESULTS: The mean age of the patients was 38 years (range, 22-58). Squamous metaplasia was present in 19 cases (65.5%), and well-differentiated endometrioid adenocarcinoma coexisted in 5 cases (17.2%). Primary treatment consisted of dilatation and curettage in 9 patients (31.0%), vaginal resection in 2 patients (6.9%), hysteroscopic transcervical resection (TCR) using hysteroscopy in 10 patients (34.5%), and hysterectomy in 8 patients (27.6%). There were recurrences in 5 (23.8%) of the 21 cases in which fertility was preserved, and the recurrent rate was 10% (1/10) in patients those were treated with TCR and 36.4% (4/11) in those the other treatment options were selected. All patients were alive after primary treatment (a mean follow-up period was 39.6 months; range, 1-202). CONCLUSION: The clinical outcome of APAM is benign. However, differential diagnosis should be performed because of its histological similarity to invasive endometrial carcinoma and the possibility of coexistence with other endometrial neoplasms. TCR is a recommended diagnostic and treatment option for patients who desire to preserve fertility.

Clinical impact of systematic pelvic and para-aortic lymphadenectomy for pT1 and pT2 ovarian cancer: a retrospective survey by the Sankai Gynecology Study Group.

BACKGROUND: The therapeutic value of systematic lymphadenectomy for early-stage epithelial ovarian cancer (EOC) is controversial. This study evaluates the survival impact and adverse events of systematic pelvic and para-aortic lymphadenectomy in patients with pT1 and pT2 EOC. METHODS: A retrospective investigation was performed using data from patients with pT1 and pT2 EOC at multi-institutions belonging to the Sankai Gynecologic Study Group (SGSG). We selected patients who had undergone systematic pelvic and para-aortic lymphadenectomy (Group LA) (n = 284) and patients who had not undergone lymph node resection (Group no-LA) (n = 138). Outcomes for patients and peri-operative adverse events were compared between the two groups. RESULTS: The median operation time was significantly longer in Group LA (288 min) than in Group no-LA (128 min) (P < 0.0001). Total blood loss was significantly higher in Group LA, 43.7 % of patients receiving blood transfusions. There were no significant differences between the treatment groups for progression-free survival (PFS) or overall survival (OS). However, for patients with pT2, PFS was significantly longer in Group LA than in Group no-LA (P = 0.0150). Lymph node metastases were detected in 23 cases (8.1 %) and these patients had significantly shorter PFS than those without metastasis (P = 0.0409). The outcome for patients who underwent chemotherapy after surgery was significantly improved in the Group no-LA, but no improvement was observed in Group LA. CONCLUSIONS: Systematic lymphadenectomy may improve outcomes only in pT2 EOC patients with acceptable peri-operative events. Furthermore, accurate surgical staging may avoid unnecessary adjuvant chemotherapy in selected early-stage cases.

Phase II study of neoadjuvant chemotherapy with irinotecan hydrochloride and nedaplatin followed by radical hysterectomy for bulky stage Ib2 to IIb, cervical squamous cell carcinoma: Japanese Gynecologic Oncology Group study (JGOG 1065).

The efficacy and adverse events of neoadjuvant chemotherapy with irinotecan hydrochloride and nedaplatin were evaluated in patients with bulky stage Ib2 to IIb cervical squamous cell carcinoma. Eligibility included patients who received irinotecan (60 mg/m2) on days 1 and 8 and nedaplatin (80 mg/m2) on day 1 of a 21-day cycle. After 1-3 courses of chemotherapy, radical hysterectomy was performed. Sixty-eight patients were enrolled. Sixty-six were included in the full analysis set. Their median age was 47 years (range 22-71), the FIGO stage was Ib2 in 18 patients, IIa in 10, and IIb in 38. Radical hysterectomy was performed after NAC in 63 patients (95.5%). The number of administered courses of NAC was 1 in 13 patients, 2 in 43, and 3 in 10. The response rate, the primary endpoint of this study, was 75.8% (CR in 2 patients, PR in 48, SD in 12, PD in 0, and NE in 4). The mean number of treatment courses required for a response was 1.42 (1 course in 30 patients, 2 courses in 19, and 3 courses in 1). The incidences of grade 3 or 4 hematological toxicities were: neutropenia 72.2%, leukopenia 16.7%, anemia 13.6%, thrombocytopenia 7.6%, febrile neutropenia 1.5%, and elevations of alanine aminotransferase and aspartate aminotransferase 1.5%. Grade 3 or 4 non-hematologic toxicities were as follows: diarrhea 6.1%, nausea 3%, anorexia 1.5%, vomiting 1.5%, fever 1.5%, allergic reactions 1.5%, ileus 1.5% and vesicovaginal fistula 1.5%. Neoadjuvant chemotherapy with irinotecan and nedaplatin was an effective and well-tolerated treatment for patients with bulky stage Ib2 to IIb squamous cell carcinoma of the uterine cervix.

New terminology for intrauterine endometrial samples: a group study by the Japanese Society of Clinical Cytology.

OBJECTIVE: To evaluate the sensitivity and specificity of endometrial cytology obtained by intrauterine sample using a descriptive reporting format for endometrial cytological diagnosis. STUDY DESIGN: 10,152 consecutive endometrial scrapings obtained in 13 different Japanese hospitals were analyzed. Cytological results were classified as 'negative for malignancy', 'atypical endometrial cells' (ATEC), 'endometrial hyperplasia', 'atypical endometrial hyperplasia' or 'malignant tumor'. ATEC was subclassified as 'ATEC, of undetermined significance' (ATEC-US) and 'ATEC, cannot exclude atypical endometrial hyperplasia or more' (ATEC-A). Cytological results were compared with the histological diagnosis as a gold standard. When the cytological result was 'negative for malignancy' and there was no subsequent histological examination, the case was considered a true negative when the endometrium was assessed as normal on transvaginal ultrasonography and there was no abnormal uterine bleeding. RESULTS: 1,083 cases in which histology was not performed, 557 cases of 'unsatisfactory specimen' and 76 cases of ATEC-US were excluded. In the remaining 8,436 cases, the sensitivity and specificity, positive predictive value and negative predictive value for detecting atypical endometrial hyperplasia or malignant tumors were 79.0 and 99.7, 92.9 and 98.9%, respectively. CONCLUSION: The current diagnostic standards for endometrial cytology in Japan were established. Specificity is satisfactory for excluding cancer or precancerous diseases.

A randomized phase III trial of IV carboplatin and paclitaxel × 3 courses followed by observation versus weekly maintenance low-dose paclitaxel in patients with early-stage ovarian carcinoma: a Gynecologic Oncology Group Study.

OBJECTIVE: To compare the recurrence-free interval (RFI) and safety profile in patients with completely resected high-risk early-stage ovarian cancer treated with intravenous (IV) carboplatin and paclitaxel with or without maintenance low-dose paclitaxel for 24 weeks. METHODS: Eligibility was limited to patients with stage IA/B (grade 3 or clear cell), all IC or II epithelial ovarian cancer. All patients were to receive carboplatin AUC 6 and paclitaxel 175 mg/m² q3 weeks × 3 courses with random assignment to either observation or maintenance paclitaxel 40 mg/m²/week × 24 weeks. Recurrence required clinical or radiological evidence of new tumor. RESULTS: There were 571 patients enrolled onto this study, of whom 29 were deemed ineligible due to inappropriate stage or pathology, leaving 542 patients. At least 3 cycles of treatment were administered to 524/542 (97%) of patients, and among those assigned to maintenance paclitaxel, 80% completed the regimen. The incidence of grade 2 or worse peripheral neuropathy (15.5% vs. 6%), infection/fever (19.9% vs. 8.7%), and dermatologic events (70.8% vs. 52.1%) was higher on the maintenance regimen (p<0.001). The cumulative probability of recurring within 5 years for the maintenance paclitaxel regimen is 20% vs. 23% for surveillance (hazard ratio 0.807; 95% CI: 0.565-1.15). The probability of surviving 5 years was 85.4% and 86.2%, respectively. CONCLUSION: Maintenance paclitaxel at 40 mg/m²/week × 24 weeks added to standard dose AUC6 and paclitaxel 175 mg/m² × 3 doses provides no significant increase in RFI.

A phase II clinical trial of topotecan in Japanese patients with relapsed ovarian carcinoma.

OBJECTIVE: This Phase II study was carried out to investigate the efficacy, safety and pharmacokinetics of topotecan in Japanese patients with relapsed ovarian carcinoma. METHODS: Patients with relapsed ovarian carcinoma after having received one regimen containing platinum-based chemotherapy were eligible for this study. Topotecan was administered at 1.2 mg/m(2)/day for five consecutive days, repeated every 3 weeks. RESULTS: Seventy-two patients were enrolled in the study. The response rate was 28.2% (95% confidence interval, 18.1-40.1%). Signs of myelosuppression, such as neutropenia (Grade 3, 12.5%; Grade 4, 83.3%), thrombocytopenia (Grade 3, 36.2%; Grade 4, 4.2%) and decreased hemoglobin (Grade 3, 36.1%; Grade 4, 11.1%), were the most common hematological toxicities. Grade 3 febrile neutropenia occurred in 5 (6.9%) patients. There was little intraindividual or interindividual variability in the pharmacokinetics of topotecan. CONCLUSIONS: Topotecan at 1.2 mg/m(2)/day is an effective and tolerable therapeutic option for Japanese patients with relapsed ovarian carcinoma.

Evidence-based guidelines for treatment of uterine body neoplasm in Japan: Japan Society of Gynecologic Oncology (JSGO) 2009 edition.

Endometrial carcinoma is one of the most common gynecologic malignancies in Japan and its incidence has increased recently. Although surgery is the cornerstone of the management of patients with endometrial cancer, there is significant variation in Japan with regard to the type of hysterectomy employed. Additionally, it remains controversial whether full nodal staging is required in all patients. Furthermore, adjuvant therapy differs between Japan and Western countries. To delineate clearly the standard of care for endometrial cancer treatment in Japan, the guidelines for the treatment of endometrial cancer were published in 2006 and revised in 2009. The 2009 edition included topics not addressed in the previous edition including the treatment of mesenchymal tumors, for example leiomyosarcoma, and sections covering the treatment of serous and clear-cell adenocarcinoma. These guidelines are composed of nine chapters and include nine algorithms. The guidelines also contain fifty-one clinical questions (CQs) and each CQ consists of recommendations, background, explanations, and references. The treatment recommendations herein are tailored to reflect current Japanese clinical practice and ensure equitable care for all Japanese women diagnosed with endometrial cancer.

Long-term survival in patients with para-aortic lymph node metastasis with systematic retroperitoneal lymphadenectomy followed by adjuvant chemotherapy in endometrial carcinoma.

OBJECTIVE: The purposes of this study were to assess modified radical hysterectomy including systematic pelvic and para-aortic lymphadenectomy followed by adjuvant chemotherapy in patients with para-aortic lymph node (PAN) metastasis in endometrial carcinoma and to identify the multivariate independent prognostic factors for long-term survival during the past 10 years. METHODS: Between December 1987 and December 2002, we performed modified radical hysterectomy with bilateral salpingo-oophorectomy including systematic pelvic and para-aortic lymphadenectomy and peritoneal cytology in 284 endometrial carcinoma patients according to the classification of the International Federation of Gynecology and Obstetrics (stage IA, n = 66; stage IB, n = 96; stage IC, n = 33; stage IIA, n = 5; stage IIB, n = 20; stage IIIA, n = 28; stage IIIC, n = 28; and stage IV, n = 8) who gave informed consents at our institute. Patients with tumor confined to the uterus (stages IC and II) were treated by 3 courses of cyclophosphamide 750 mg/m2, epirubicin 50 mg/m2, and cisplatin 75 mg/m2 regimen 3 to 4 weeks apart, and patients with extrauterine lesions involving adnexa and/or pelvic lymph node (PLN) were treated by 5 courses. In addition, 10 courses were given to patients with PAN metastasis. Patients with PLN metastasis received adjuvant chemotherapy, and adjuvant radiation was not part of our institutional protocol. For multivariate regression modeling with proportional hazards, the regression model of Cox was used. Survival curves were analyzed by the Kaplan-Meier method, and analysis of the differences was performed by the log-rank test. RESULTS: The overall incidence of retroperitoneal lymph node metastasis assessed by systematic pelvic and para-aortic lymphadenectomy was 12.0% (34/284) in stages I to IV endometrial carcinoma, and incidences of PLN and PAN metastases were 9.2% (26/284) and 7.4% (21/284), respectively. However, PAN metastasis rate is 50% (13/26) in patients with PLN metastasis. Univariate analysis of prognostic factors revealed that International Federation of Gynecology and Obstetrics clinical stage (P < 0.0001), histological finding (P = 0.0292), myometrial invasion (P < 0.0001), adnexal metastasis (P < 0.0001), lymphovascular space invasion (P < 0.0001), tumor diameter (P = 0.0108), peritoneal cytology (P = 0.0001), and retroperitoneal lymph node metastasis (P < 0.0001) were significantly associated with 10-year overall survival. Survival was not associated with age (P = 0.1558) or cervical involvement (P = 0.1828). A multivariate analysis showed that adnexal metastasis (P = 0.0418) and lymphovascular space invasion (P = 0.0214) were significantly associated with 10-year overall survival. The 5- and 10-year overall survival rates in patients with negative PAN were 96% and 93% versus 72% and 62% in patients with positive PAN (P = 0.006). CONCLUSIONS: It is suggested that surgery with systematic pelvic and para-aortic lymphadenectomy followed by adjuvant chemotherapy could improve long-term survival in patients with PAN metastasis, although there are only 21 patients with PAN metastasis.

The importance of precise pT diagnosis for prognostic prediction of uterine cervical cancer--a single institutional report at a Japanese comprehensive cancer hospital.

We previously reported that the majority of Japanese pathologists misunderstand the International Union against Cancer-pT2 criteria for uterine cervical cancer (UCC). We compared the prognosis of originally diagnosed pT2 (ori-pT) UCC cases at our hospital with reclassified pT2 (re-pT) cases to assess the importance of making a correct pT diagnosis. There were 43 International Federation of Gynecology and Obstetrics (FIGO) II (i.e., cT2) and/or ori-pT2 UCC cases who received surgery without neoadjuvant chemotherapy at Shikoku Cancer Center from 1991 to 2003. The cases (seven ori-pT1 and 36 ori-pT2; 43 cN0 with six pN1) were reclassified as 22 re-pT1 and 21 re-pT2. Fifteen of the 23 ori-pT2a cases (65%) were re-pT1 because their vaginal extension had only been intraepithelial. The difference in the 5-year survival rate (5Y-SR) was not significant between the ori-pT1 and ori-pT2 cases using Fisher's exact test (F test): P = 0.236 > 0.05, whereas 5Y-SR of re-pT1 cases was significantly higher than re-pT2, including pN1 cases and excluding them (F test: P = 0.00164 < 0.01 and P = 0.0108 < 0.05, respectively). The 5Y-SR of ori-pT2-re-pT1 (overdiagnosed pT2) was significantly higher that of ori-pT2-re-pT2 (true pT2) including pN1 cases and excluding them (F test: P = 0.00694 < 0.01 and P = 0.0305 < 0.05, respectively). These results indicated that pT2 of UCC could be frequently misdiagnosed at an institutional level, and that misdiagnosed pT2 might impair the evidence-based medicine of UCC. Multi-institutional assessment of the accuracy of pTNM is recommended, because it is not likely that this is an endemic problem to our hospital.

Clinicopathological characteristics of mucinous adenocarcinoma of the ovary.

OBJECTIVE: We conducted the present study to clarify the clinicopathological characteristics of mucinous adenocarcinoma. METHODS: Two hundred twenty-five patients were diagnosed with mucinous adenocarcinoma at individual institutes and underwent primary treatment between 1998 and 2003. Of these patients, 189 patients who could undergo central pathological review were enrolled in this study. Of 189 patients undergoing central pathological review, 64 patients (33.9%) were diagnosed with mucinous invasive adenocarcinoma, 45 mucinous intraepithelial carcinoma, and 42 mucinous tumor of borderline malignancy. Twenty-five patients were diagnosed with other histological subtypes, including 8 endometrioid adenocarcinoma, 5 clear cell carcinoma, 3 serous adenocarcinoma, and 4 mixed type. There were 13 cases of metastatic mucinous adenocarcinoma, including 7 pseudomyxoma peritonei. Four hundred thirty-three patients with serous adenocarcinoma were used as controls. RESULTS: Forty-five patients with mucinous invasive carcinoma were in FIGO I-II stages and 19 in III-IV stages. There was no difference in the outcome between mucinous invasive adenocarcinoma and serous adenocarcinoma in I-II stage patients and III-IV stage patients with optimal operation. In contrast, patients with mucinous invasive adenocarcinoma receiving suboptimal operation showed a significantly worse prognosis (survival rate: 27.8% vs. 61.5%). The response rate to chemotherapy for mucinous invasive adenocarcinoma was significantly lower than for serous adenocarcinoma (12.5% vs. 67.7%). CONCLUSIONS: The diagnosis of mucinous invasive adenocarcinoma was difficult. Since patients with mucinous invasive adenocarcinoma had a lower response to chemotherapy, aggressive cytoreductive surgery was an effective treatment to improve the prognosis for advanced stage patients. A new chemotherapeutic regimen should be established for mucinous adenocarcinoma of the ovary.

Multicenter phase II study of fertility-sparing treatment with medroxyprogesterone acetate for endometrial carcinoma and atypical hyperplasia in young women.

PURPOSE: To assess the efficacy of fertility-sparing treatment using medroxyprogesterone acetate (MPA) for endometrial carcinoma (EC) and atypical endometrial hyperplasia (AH) in young women. PATIENTS AND METHODS: This multicenter prospective study was carried out at 16 institutions in Japan. Twenty-eight patients having EC at presumed stage IA and 17 patients with AH at younger than 40 years of age were enrolled. All patients were given a daily oral dose of 600 mg of MPA with low-dose aspirin. This treatment continued for 26 weeks, as long as the patients responded. Histologic change of endometrial tissue was assessed at 8 and 16 weeks of treatment. Either estrogen-progestin therapy or fertility treatment was provided for the responders after MPA therapy. The primary end point was a pathologic complete response (CR) rate. Toxicity, pregnancy rate, and progression-free interval were secondary end points. RESULTS: CR was found in 55% of EC cases and 82% of AH cases. The overall CR rate was 67%. Neither therapeutic death nor irreversible toxicities were observed; however, two patients had grade 3 body weight gain, and one patient had grade 3 liver dysfunction. During the 3-year follow-up period, 12 pregnancies and seven normal deliveries were achieved after MPA therapy. Fourteen recurrences were found in 30 patients (47%) between 7 and 36 months. CONCLUSION: The efficacy of fertility-sparing treatment with a high-dose of MPA for EC and AH was proven by this prospective trial. Even in responders, however, close follow-up is required because of the substantial rate of recurrence.

[Prediction of pelvic control using MRI for patients with cervical carcinoma treated with radiotherapy].

PURPOSE: To investigate the usefulness of MRI for predicting pelvic control (PC) of cervical cancer treated with radiation therapy (RT). MATERIALS AND METHODS: Forty-four cervical cancer patients treated with definitive RT were retrospectively analyzed. MRIs were completed before and after RT, and the longest diameter (LD) of the residual tumor was measured on post-RT MRI. Pathologic evaluation for residual tumor was also performed. Therapeutic response was assessed using MRI. Median follow-up time for the 44 patients was 34 months. The correlations between PC rate, MRI, and pathological findings were investigated. RESULTS: The 3-year PC rates of LD = 0 cm (n = 23) after RT, 0 < LD 2 cm (n = 6) were 85%, 80%, and 0%, respectively (p < 0.0001). There was no significant difference in PC according to the presence (n = 8) or absence (n = 36) of residue in the pathologic materials (3-year PC rate: 63% vs. 77%). Three-year PC rates according to therapeutic responses were 85% in complete response (n = 23), 72% in partial response (n = 18), and 0% in stable disease or progressive disease (n = 3) (p < 0.0001). CONCLUSION: MRI is useful for predicting PC in cervical cancer treated with RT, and LD greater than 2 cm after RT is a good marker for poor PC.

Adenoid basal carcinoma of the uterine cervix: report of two cases with reference to adenosquamous carcinoma.

Adenoid basal carcinoma (ABC) of the uterine cervix is a rare neoplasm with excellent prognosis. Differential diagnosis between ABC and an ABC-like lesion of adenosquamous cell carcinoma (ASC) of the cervix is important due to their contrasting prognosis. Reported herein are two cases of ABC that have been compared with seven ASC exhibiting ABC-like lesions from approximately 2600 resected uterine cervical malignancies diagnosed at Shikoku Cancer Center. The two ABC were incidentally found in the uterine cervix of 69-year-old and 59-year-old Japanese women due to cervical intraepithelial neoplasia grade 3 and to squamous cell carcinoma, respectively. The ABC consisted of infiltrating nests of basaloid cells with low nuclear atypia. The patients remained alive without recurrence for 9 years and 18 months, respectively. An ABC-like lesion was defined as basaloid cell nests simulating ABC, but with some features indicating malignant potential. However, the differential diagnosis was sometimes difficult because two of seven ABC-like lesions were originally diagnosed as ABC. Immunohistochemically, cytokeratin 7 was negative for the basaloid cells of two ABC, but positive for six of six ABC-like lesions of ASC, while cytokeratin 8 was positive for both ABC and ASC. This cytokeratin pattern might provide a good tool for distinguishing between ABC and an ABC-like lesion of ASC when the histological findings are equivocal.