The many faces of pseudomyxoma peritonei: a radiological review based on 30 cases / As múltiplas faces do pseudomixoma peritonial: uma revisão radiológica baseada em 30 casos

Abstract Objective: To determine the most common imaging features of pseudomyxoma peritonei (PMP), as well as the histologic subtypes of the primary tumors. Materials and Methods: We reviewed 30 cases of women with pathologically confirmed PMP. Only computed tomography scans were available. All cases were retrospectively studied by four radiologists, working independently. We identified the most common imaging findings, the predominant primary site of the disease, and the growth pattern. The most common sites of recurrence were also analyzed. Results: The most common computed tomography finding was peritoneal/omental nodules (including "omental caking"), followed by visceral scalloping and non-mucinous ascites. The most common site of the primary tumor was the appendix (in 63.3%), followed by the ovaries (in 16.6%), and 16.6% of the tumors were of undetermined origin. There was one case of synchronous appendiceal and ovarian tumors. Low-grade mucinous neoplasm was the most common histologic subtype, accounting for 84.2% of the appendiceal tumors and 40% of the ovarian tumors. Conclusion: Although PMP is a relatively rare entity, radiologists must be aware of its possible imaging findings, common locations, and possible patterns of recurrence. The origin of the primary tumor should also be investigated. Future studies are needed in order to determine which preoperative imaging findings predict surgical outcomes and to characterize the main findings of radiological recurrence.

Resumo Objetivo: Determinar as características de imagem mais frequentes do pseudomixoma peritonial (PMP), bem como os subtipos histológicos dos tumores primários. Materiais e Métodos: Foram revisados 30 casos confirmados patologicamente de PMP em mulheres. Somente a tomografia computadorizada estava disponível. Todos os casos foram estudados de forma independente e retrospectiva por quatro radiologistas. Os autores relataram os achados de imagem mais frequentes, a localização predominante da doença primária e o padrão de crescimento. Os locais de recorrência mais comuns também foram analisados. Resultados: Os achados tomográficos mais frequentes foram nódulos peritoniais/omentais (incluindo "bolo omental"), seguidos por scalloping visceral e ascite não mucinosa. Os padrões de localização mais comuns do PMP também foram documentados. A grande maioria dos tumores primários foi de origem apendicular (63,3%), seguida de origem ovárica (16,6%) e indeterminada (16,6%). Houve um caso síncrono de tumor apendicular e ovário. A neoplasia mucinosa de baixo grau foi o subtipo histológico mais frequente, representando 84,2% dos tumores do apêndice e 40% dos tumores primários ovarianos. Conclusão: Embora o PMP continue sendo uma entidade relativamente rara, o radiologista deve estar ciente de seus possíveis achados de imagem, locais comuns e possíveis padrões de recorrência. A investigação do tumor primário também deve ser encorajada. Futuros estudos são necessários para prever o resultado cirúrgico da imagem pré-operatória e caracterizar os principais achados de recorrência radiológica.

The added value of diffusion-weighted imaging in the preoperative assessment of endometrial cancer.

OBJECTIVE: To evaluate the added value of diffusion-weighted imaging (DWI) in the preoperative assessment of myometrial invasion in endometrial cancer, in comparison with T2-weighted imaging (T2WI) and dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI). MATERIALS AND METHODS: This was a retrospective study involving 44 women with endometrial cancer who underwent preoperative 1.5 T MRI. Two radiologists, both of whom were blinded to the histopathology reports, performed a consensus interpretation of the depth of myometrial invasion and of the stage of the cancer, considering three sets of sequences: T2WI, DCE-MRI+T2WI, and DWI+T2WI. Accuracy, sensitivity, specificity, positive predictive value, and negative predictive value were calculated for each set. The accuracy was compared with p-value adjustment by the Benjamini-Hochberg procedure. RESULTS: Among the 44 patients evaluated, DWI+T2WI demonstrated better diagnostic performance in assessing deep myometrial invasion and correctly staged more patients (n = 41) than did DCE-MRI+T2WI (n = 34) and T2WI (n = 22). The superior diagnostic accuracy of DWI+T2WI was statistically significant in comparison with T2WI (p < 0.05) but not in comparison with DCE-MRI+T2WI (p > 0.05). CONCLUSION: The addition of DWI apparently improves the diagnostic accuracy of MRI in the preoperative assessment of the depth of myometrial invasion in endometrial cancer, which may be particularly helpful in patients for whom contrast agents are contraindicated.

OBJETIVO: Determinar o valor adicional da difusão (DWI) em ressonância magnética (RM) na avaliação pré-operatória da invasão miometrial do câncer do endométrio, em comparação com sequências T2 e com o estudo dinâmico após contraste paramagnético (dynamic contrast-enhanced - DCE). MATERIAIS E MÉTODOS: Estudo retrospectivo incluindo 44 mulheres com câncer do endométrio que realizaram RM 1,5 T pré-operatória. Dois radiologistas desconhecendo a histopatologia final realizaram interpretação consensual sobre a profundidade de invasão miometrial e o estádio da doença considerando três conjuntos de sequências: T2, DCE+T2 e DWI+T2. Para cada conjunto foram calculadas acuidade, sensibilidade, especificidade, valor preditivo positivo e valor preditivo negativo. A acuidade diagnóstica foi comparada com ajuste do valor de p utilizando o procedimento Benjamini-Hochberg. RESULTADOS: DWI+T2 apresentou melhor performance diagnóstica na avaliação da invasão miometrial e permitiu estadiar corretamente mais pacientes (41/44) do que DCE+T2 (34/44) e T2 (22/44). A superior acuidade diagnóstica da DWI+T2 foi estatisticamente significativa quando comparada com T2 (p < 0,05), mas não quando comparada com DCE+T2 (p > 0,05). CONCLUSÃO: A interpretação da DWI+T2 melhorou a acuidade diagnóstica da RM na avaliação pré-operatória da invasão miometrial do câncer de endométrio, o que poderá ser particularmente útil em pacientes com contraindicação para contraste paramagnético.

The added value of diffusion-weighted imaging in the preoperative assessment of endometrial cancer / A acurácia do estudo de difusão na avaliação pré-operatória do carcinoma do endométrio

Abstract Objective: To evaluate the added value of diffusion-weighted imaging (DWI) in the preoperative assessment of myometrial invasion in endometrial cancer, in comparison with T2-weighted imaging (T2WI) and dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI). Materials and Methods: This was a retrospective study involving 44 women with endometrial cancer who underwent preoperative 1.5 T MRI. Two radiologists, both of whom were blinded to the histopathology reports, performed a consensus interpretation of the depth of myometrial invasion and of the stage of the cancer, considering three sets of sequences: T2WI, DCE-MRI+T2WI, and DWI+T2WI. Accuracy, sensitivity, specificity, positive predictive value, and negative predictive value were calculated for each set. The accuracy was compared with p-value adjustment by the Benjamini-Hochberg procedure. Results: Among the 44 patients evaluated, DWI+T2WI demonstrated better diagnostic performance in assessing deep myometrial invasion and correctly staged more patients (n = 41) than did DCE-MRI+T2WI (n = 34) and T2WI (n = 22). The superior diagnostic accuracy of DWI+T2WI was statistically significant in comparison with T2WI (p < 0.05) but not in comparison with DCE-MRI+T2WI (p > 0.05). Conclusion: The addition of DWI apparently improves the diagnostic accuracy of MRI in the preoperative assessment of the depth of myometrial invasion in endometrial cancer, which may be particularly helpful in patients for whom contrast agents are contraindicated.

Resumo Objetivo: Determinar o valor adicional da difusão (DWI) em ressonância magnética (RM) na avaliação pré-operatória da invasão miometrial do câncer do endométrio, em comparação com sequências T2 e com o estudo dinâmico após contraste paramagnético (dynamic contrast-enhanced - DCE). Materiais e Métodos: Estudo retrospectivo incluindo 44 mulheres com câncer do endométrio que realizaram RM 1,5 T pré-operatória. Dois radiologistas desconhecendo a histopatologia final realizaram interpretação consensual sobre a profundidade de invasão miometrial e o estádio da doença considerando três conjuntos de sequências: T2, DCE+T2 e DWI+T2. Para cada conjunto foram calculadas acuidade, sensibilidade, especificidade, valor preditivo positivo e valor preditivo negativo. A acuidade diagnóstica foi comparada com ajuste do valor de p utilizando o procedimento Benjamini-Hochberg. Resultados: DWI+T2 apresentou melhor performance diagnóstica na avaliação da invasão miometrial e permitiu estadiar corretamente mais pacientes (41/44) do que DCE+T2 (34/44) e T2 (22/44). A superior acuidade diagnóstica da DWI+T2 foi estatisticamente significativa quando comparada com T2 (p < 0,05), mas não quando comparada com DCE+T2 (p > 0,05). Conclusão: A interpretação da DWI+T2 melhorou a acuidade diagnóstica da RM na avaliação pré-operatória da invasão miometrial do câncer de endométrio, o que poderá ser particularmente útil em pacientes com contraindicação para contraste paramagnético.

T2 hyperintense myometrial tumors: can MRI features differentiate leiomyomas from leiomyosarcomas?

PURPOSE: To establish MRI features that help differentiate atypical leiomyomas and leiomyomas with degeneration that show hyperintensity on T2WI from leiomyosarcomas. METHODS AND MATERIALS: This retrospective study evaluated 41 women who performed MRI before undergoing hysterectomy and had histologically proven atypical leiomyomas, leiomyomas with degeneration or leiomyosarcomas (21 leiomyomas; 20 leiomyosarcomas); only patients with T2 hyperintense myometrial tumors were included. The association between MRI features (contours; free pelvic fluid; intra-tumoral hemorrhagic areas, T2 heterogeneity; T2 dark areas; flow voids; restriction on diffusion-weighted images; signal intensity and heterogeneity after contrast administration; unenhanced areas, localization of unenhanced areas; necrosis; cystic areas) and the histology (leiomyoma vs. leiomyosarcoma) were calculated using Fisher's exact test. For those features that showed a significant association, a univariate linear regression was performed. RESULTS: Five MRI features demonstrated a significant correlation with malignant histology: irregular borders (p = 0.03); "T2 dark" areas (p = 0.02); presence of central necrosis (p = 0.01); presence of high signal on b1000 DWI (p < 0.001); ADC value lower than 0.82 × 10-3 mm2/s; hyperenhancement of the tumor relative to the myometrium on post-contrast images (p = 0.02); and type 3 enhancing curve on DCE. Two of these features demonstrated a significant result predicting a malignant histology: lobulated contours and central necrosis [F(3;34) = 8,95; p < 0.001; R2 = 0.506]. CONCLUSION: The presence of lobulated borders, T2 dark areas, necrosis, hyperintensity relative to the myometrium after contrast administration, central necrosis, presence of high signal on b1000 DWI, ADC value lower than 0.82 × 10-3 mm2/s and type 3 enhancing curve on DCE can help distinguish between leiomyoma and leiomyosarcoma. The association of lobulated borders and central necrosis can help predict a malignant histology.

The many faces of pseudomyxoma peritonei: a radiological review based on 30 cases.

OBJECTIVE: To determine the most common imaging features of pseudomyxoma peritonei (PMP), as well as the histologic subtypes of the primary tumors. MATERIALS AND METHODS: We reviewed 30 cases of women with pathologically confirmed PMP. Only computed tomography scans were available. All cases were retrospectively studied by four radiologists, working independently. We identified the most common imaging findings, the predominant primary site of the disease, and the growth pattern. The most common sites of recurrence were also analyzed. RESULTS: The most common computed tomography finding was peritoneal/omental nodules (including "omental caking"), followed by visceral scalloping and non-mucinous ascites. The most common site of the primary tumor was the appendix (in 63.3%), followed by the ovaries (in 16.6%), and 16.6% of the tumors were of undetermined origin. There was one case of synchronous appendiceal and ovarian tumors. Low-grade mucinous neoplasm was the most common histologic subtype, accounting for 84.2% of the appendiceal tumors and 40% of the ovarian tumors. CONCLUSION: Although PMP is a relatively rare entity, radiologists must be aware of its possible imaging findings, common locations, and possible patterns of recurrence. The origin of the primary tumor should also be investigated. Future studies are needed in order to determine which preoperative imaging findings predict surgical outcomes and to characterize the main findings of radiological recurrence.

Mature cystic teratoma with high proportion of solid thyroid tissue: a controversial case with unusual imaging findings.

We describe a case of a mature cystic teratoma of the ovary with high proportion of solid thyroid tissue (< 50% of the entire tumor) in a childbearing woman. The patient presented with non-specific abdominal bloating. Pelvic ultrasound and magnetic resonance imaging revealed a complex cystic-solid tumor confined to the left ovary with an anterior fat-containing locus compatible with mature cystic teratoma and a posterior predominantly solid component with low signal intensity on T2-weighted images that was histopatologically diagnosed as benign thyroid tissue. Thyroglobulin levels were in normal range. Although thyroid tissue is present in up to 20% of mature cystic teratomas, with exception of struma ovarii, it is not usually macroscopically nor radiologically identified. The differential diagnosis should include T2-hypointense adnexal lesions associated with mature cystic teratoma, malignant transformation of mature teratoma, and immature teratoma.