Ischiorectal fossa: benign and malignant neoplasms of this "ignored" radiological anatomical space

Anal and Perianal Masses: The Common, the Uncommon, and the Rare

A variety of tumors involve the anal canal because the anal canal forms the transition between the digestive system and the skin, and this anatomical region is made of a variety of different cells and tissues. Magnetic resonance imaging (MRI) is the modality of choice for diagnosis and local staging of the anal canal and perianal neoplasms. In this pictorial review, we demonstrate the MRI anatomy of the anal canal and perianal region and display the imaging spectrum of tumors in the region along with an overview of its management. Imaging appearances of many tumorlike lesions that can cause diagnostic dilemmas are also demonstrated with pointers to differentiate between them.

Update on Pathologic Conditions, Imaging Findings, Prevention, and Management of Human Papillomavirus-related Neoplasms

Human papillomavirus (HPV) is the most common sexually transmitted infection that proliferates in the squamous epithelium and is the most common source of viral-related neoplasms. Low-risk subtypes (HPV-6 and -11) cause respiratory papillomas (laryngeal, tracheal, and bronchial) and condyloma acuminata of the penis, anus, and perineal region (anogenital warts). High-risk subtypes (HPV-16, -18, -31, and -33) are responsible for oropharyngeal squamous cell carcinoma (SCC) that involves the tongue base, tonsils, posterior pharyngeal wall, and larynx and malignancies of the anogenital region (cancers of the cervix, vagina, vulva, penis, and anal canal). Recent studies have increasingly shown a favorable treatment response and substantial differences in the overall prognosis associated with HPV-associated oropharyngeal cancers. Given this fact, oropharyngeal, cervical, and penile SCCs are classified as HPV-associated and HPV-independent cancers in the current World Health Organization classification. Imaging is essential in the early detection, diagnosis, and staging of HPV-associated cancers. Imaging also helps assess treatment response and postoperative complications and is used for long-term surveillance. HPV-associated oropharyngeal SCCs have well-defined borders and solid and cystic nodal metastases at imaging. Updated screening and vaccination guidelines are currently available that have great potential to decrease the overall disease burden and help control this worldwide public health concern. Novel therapeutic strategies, such as immunotherapies, are being explored, and imaging biomarkers that can predict treatment response and prognosis are being investigated; radiologists play a pivotal role in these efforts. ©RSNA, 2024 Supplemental material is available for this article.

Ischiorectal Fossa Tumors: 30-year Single-Institution Experience

BACKGROUND

Primary tumors of the ischiorectal fossa are rare and comprise a wide array of pathologies with varying malignant potential. Because of the low prevalence, there is a paucity of data in the literature. This article presents a case series on the management of ischiorectal fossa tumors.

OBJECTIVE

To present experience from 30 years of managing ischiorectal fossa tumors.

DESIGN

Retrospective single-center analysis.

SETTINGS

A quaternary referral academic health care center.

PATIENTS

All patients treated for ischiorectal fossa tumors were included in the study.

INTERVENTIONS

All patients underwent surgical management of their disease.

MAIN OUTCOME MEASURES

Disease recurrence and overall survival.

RESULTS

A total of 34 patients (53% women) were identified with a median follow-up of 23 months. Twenty-one patients (62%) were diagnosed with benign and 13 (38%) with malignant tumors. All underwent surgical resection. The median tumor size was 8.4 cm. R0 resection was obtained in 28 patients. Twelve patients (35%) developed recurrence (9 after R0 resection) after a median time of 6.5 months. There were no surgical-related mortalities.

LIMITATIONS

Limitations to the study include its retrospective nature, single-center experience, and small patient sample size.

CONCLUSIONS

Ischiorectal fossa tumors are primarily benign; however, they are associated with high recurrence rates even in the setting of an R0 resection. Treatment should be approached in a multidisciplinary manner, preferably in centers with experience treating these tumors. Close posttreatment surveillance is imperative. See Video Abstract .

TUMORES DE LA FOSA ISQUIORRECTAL EXPERIENCIA DE AOS EN UNA SOLA INSTITUCIN

ANTECEDENTES:Los tumores primarios de la fosa isquiorrectal son raros y comprenden una amplia gama de patologías con potencial maligno variable. Debido a la baja prevalencia, hay escasez de datos en la literatura. Este artículo presenta una serie de casos sobre el tratamiento de los tumores de la fosa isquiorrectal.OBJETIVO:Presentar una experiencia de 30 años en el manejo de tumores de la fosa isquiorrectal.DISEÑO:Análisis retrospectivo de un solo centro.AJUSTES:Un centro de atención médica académico de referencia cuaternaria.PACIENTES:Todos los pacientes tratados por tumores de la fosa isquiorrectal.INTERVENCIONES:Todos los pacientes se sometieron a tratamiento quirúrgico de su enfermedad.PRINCIPALES MEDIDAS DE RESULTADO:Recurrencia de la enfermedad y supervivencia general.RESULTADOS:Se identificaron un total de 34 pacientes (53% mujeres) con una mediana de seguimiento de 23 meses. Veintiún pacientes (62%) fueron diagnosticados con tumores benignos y 13 (38%) con tumores malignos. Todos fueron sometidos a resección quirúrgica. El tamaño medio del tumor fue de 8,4 cm. La resección R0 se obtuvo en 28 pacientes. Doce (35%) desarrollaron recurrencia (nueve después de la resección R0) con una mediana de tiempo de 6,5 meses. No hubo mortalidades relacionadas con la cirugía.LIMITACIONES:Las limitaciones del estudio incluyen su naturaleza retrospectiva, experiencia en un solo centro y tamaño pequeño de la muestra de pacientes.CONCLUSIONES:Los tumores de la fosa isquiorrectal son principalmente benignos, sin embargo, se asocian con altas tasas de recurrencia incluso en el contexto de una resección R0. El tratamiento debe abordarse de forma multidisciplinaria y preferentemente en centros con experiencia en el tratamiento de estos tumores. Vigilancia cercana posterior al tratamiento es imperativa. (Traducción-Dr. Aurian Garcia Gonzalez).

Aggressive Angiomyxoma of the Pelvis: 35-Year Experience

BACKGROUND

Aggressive angiomyxoma is a very rare mesenchymal tumor most commonly found in the pelvic and perineal regions. Although many are estrogen and progesterone hormone receptor positive, the pathogenesis is unknown. Due to its rarity, there is a paucity of literature relating to this pathology. This article presents a case series on the management of aggressive angiomyxoma of the pelvis.

OBJECTIVE

To present a 35-year experience managing aggressive angiomyxoma of the pelvis.

DESIGN

This was a retrospective single-system analysis.

SETTINGS

This study was conducted at a quaternary referral academic health care system.

PATIENTS

All patients treated for aggressive angiomyxoma of the pelvis.

INTERVENTIONS

All patients underwent surgical or medical management of their disease.

MAIN OUTCOME MEASURES

The primary outcomes were disease recurrence and mortality. Secondary outcomes included risk factors for recurrence.

RESULTS

A total of 32 patients (94% women) were identified with a median follow-up of 65 months. Thirty patients (94%) underwent operative resection and 2 patients were treated solely with medical management. Fifteen achieved an R0 resection (negative microscopic margins) at the index operation, of which 4 (27%) experienced tumor recurrence. There were no mortalities. No risk factors for disease recurrence were identified.

LIMITATIONS

Limitations to our study include its nonrandomized retrospective nature, single health care system experience, and small patient sample size.

CONCLUSIONS

Aggressive angiomyxoma is a rare, slow-growing tumor with locally invasive features and a high potential for recurrence even after resection with negative margins. Imaging modalities such as CT or MRI should be obtained to aid in diagnosis and surgical planning. Workup should be paired with preoperative biopsy and testing for hormone receptor status, which can increase diagnostic accuracy and guide medical treatment. Close posttreatment surveillance is imperative to detect recurrence. See Video Abstract .

ANGIOMIXOMA AGRESIVO DE PELVIS EXPERIENCIA DE AOS

ANTECEDENTES:El angiomixoma agresivo es un tumor mesenquimal muy raro que se encuentra más comúnmente en las regiones pélvica y perineal. Aunque muchos son positivos para los receptores hormonales como el estrógeno y la progesterona, la patogénesis es aún desconocida. Debido a su rareza, existe escasa literatura relacionada con esta patología. Este artículo presenta una serie de casos sobre el tratamiento del angiomixoma agresivo de pelvis.OBJETIVO:Presentar una experiencia de 35 años en el manejo del angiomixoma agresivo de pelvis.DISEÑO:Este fue un análisis retrospectivo de sistema único.AJUSTES:Este estudio se llevó a cabo en un sistema de salud académico de referencia de nivel cuaternario.PACIENTES:Todos los pacientes tratados por angiomixoma agresivo de pelvis.INTERVENCIONES:Todos los pacientes se sometieron a tratamiento quirúrgico y/o médico de su enfermedad.PRINCIPALES MEDIDAS DE RESULTADO:Los resultados primarios fueron la recurrencia de la enfermedad y la mortalidad. Los resultados secundarios incluyeron factores de riesgo de recurrencia.RESULTADOS:Se identificaron un total de 32 pacientes (94% mujeres) con una mediana de seguimiento de 65 meses. Treinta (94%) fueron sometidos a resección quirúrgica y dos fueron tratados únicamente con tratamiento médico. Quince lograron una resección R0 (márgenes microscópicos negativos) en la operación inicial, de los cuales cuatro (27%) experimentaron recurrencia tumoral. No hubo mortalidades. No se identificaron factores de riesgo para la recurrencia de la enfermedad.LIMITACIONES:Las limitaciones de nuestro estudio incluyen su naturaleza retrospectiva no aleatoria, la experiencia de un solo sistema de atención médica y el tamaño pequeño de la muestra de pacientes.CONCLUSIONES:El angiomixoma agresivo es un tumor raro, de crecimiento lento, con características localmente invasivas y un alto potencial de recurrencia incluso después de una resección con márgenes negativos. Se deben obtener modalidades de imágenes como CT y/o MRI para la ayuda diagnóstica y la planificación quirúrgica. El estudio debe combinarse con una biopsia preoperatoria y pruebas del estado de los receptores hormonales, que pueden aumentar la precisión del diagnóstico y guiar el tratamiento médico. Es imperativa una estrecha vigilancia posterior al tratamiento para detectar recurrencia. (Traducción-Dr Osvaldo Gauto ).

Transperineal excision of malignant peripheral nerve sheath tumors of the ischiorectal fossa: Case report of a rare tumor in a frequently forgotten anatomical region

INTRODUCTION AND IMPORTANCE

Malignant peripheral nerve sheath tumor is an aggressive tumor that arises from peripheral nerves. Frequently associated with neurofibromatosis, its common localization is in the extremities, trunk (with paravertebral regions), neck and head. Some cases have been found in the pelvis or uterus. In this case report we illustrate one of the rarest localization of this type of tumor in the ischiorectal fossa, with the full recovery of the patient after surgical excision and radiotherapy.

CASE PRESENTATION

A 61-year-old woman showed a lump near the anus which was initially diagnosed as a lipoma of the right ischiorectal fossa, by Computed Tomography scan. The tumor was completely removed with a minimal skin incision, and the patient had a complete recovery. Only the pathological examination determined the diagnosis of malignant peripheral nerve sheath tumor, in this unusual localization. In consideration of its high aggressiveness the patient underwent radiotherapy. After more than two years of follow-up there is no sign of recurrence.

DISCUSSION

In sites far from branches of nerves, malignant peripheral nerve sheath tumors can be considered episodic. Ischiorectal fossa is a rare localization, and the differential diagnosis from benign mesenchymal cell tumors can be challenging. When possible, a biopsy should be performed before surgery.

CONCLUSION

Surgical excision of tumors in ischiorectal fossa should be always complete, in consideration of possible histological surprise.

Mimics and Pitfalls of Primary Ovarian Malignancy Imaging

The complex anatomy and similarity of imaging features of various pathologies in the pelvis can make accurate radiology interpretation difficult. While prompt recognition of ovarian cancer remains essential, awareness of processes that mimic ovarian tumors can avoid potential misdiagnosis and unnecessary surgery. This article details the female pelvic anatomy and highlights relevant imaging features that mimic extra-ovarian tumors, to help the radiologists accurately build a differential diagnosis of a lesion occupying the adnexa.

Ten-Step Surgical Approach to Management of Pathology of the Ischiorectal Fossa-A Review of the Literature and Application in a Rare Pelvic Schwannoma

Objective: The ischiorectal fossa is a key anatomical location with boundaries and internal structures owing distinct contributions to function and quality of life. Methods: We highlight the importance of management of pathology in this deep anatomically complex location. Results: We present a ten-step multidisciplinary surgical approach; achieving en bloc radical excision with primary closure and reassuring outcomes. Schwannomas are benign slow-growing nerve sheath tumors. Conclusions: Pelvic schwannomas are rare with only 3 reported cases of the pudendal nerve. We also offer an overview of this rare pathology whilst acknowledging a paucity of recommendations regarding management of disease of the ischiorectal fossa.

Rare Mesenchymal Tumors of the Pelvis: Imaging and Pathologic Correlation

Most pelvic tumors originate from the organs. Less commonly, tumors can arise from the various anatomic pelvic compartments and are comprised of mesenchymal tissue: muscles, connective tissue, vessels, lymphatics, and fat. Among some of the rarer entities are benign tumors (eg, angiomyxoma, cellular angiofibroma, and desmoid fibromatosis), malignant tumors (eg, sarcoma), and tumors that can manifest as benign or malignant (eg, solitary fibrous tumor or nerve sheath tumor). Because these tumors are uncommon and often manifest with nonspecific clinical features, imaging (usually MRI) is an initial step in the evaluation. Radiologists interpreting these images are asked to help narrow the differential diagnosis and assess the likelihood of malignancy for treatment planning. Thus, the MRI report should include the imaging features that would indicate the underlying tissue histology for pathologic diagnosis as well as a description of the anatomic extent and pattern of growth. The authors describe multiple locally aggressive benign and malignant mesenchymal tumors and highlight characteristic clinical and imaging features that enable the radiologist to narrow the differential diagnosis. The anatomic spaces of the pelvis are reviewed with illustrations to aid the radiologist in describing these tumors, which often span multiple pelvic compartments. Tumor appearance at T2-weighted, diffusion-weighted, and postcontrast MRI is summarized and illustrated with correlation at CT or fluorodeoxyglucose PET/CT, when available. MRI features that correspond to specific types of tissue (eg, myxoid, fibrous, or vascular) are highlighted and correlated with images from pathologic evaluation. Online supplemental material is available for this article. ^©RSNA, 2021.

Ischiorectal fossa metastasis from colon cancer: Case report of a rare entity and review of literature

Introduction and importance

Colorectal cancer is one of the most common cancers both nationally and internationally. It commonly metastases to local lymph nodes, liver and lungs, with few reported cases of rare sites of metastasis such as adrenal glands, breast and skin.

Case presentation

We report a 55-year-old-female admitted as case of large bowel obstruction and unintentional weight loss. Computed tomography scan of chest, abdomen and pelvis (CT CAP) showed sigmoid colon circumferential thickening with three lesions in the right hemi-liver. A laparoscopic diverting ileostomy followed by a colonoscopy showed a sigmoidal mass consistent with adenocarcinoma on histopathology. Hence, she received neoadjuvant chemotherapy followed by hepatectomy for the liver metastasis. Post-operatively CT CAP showed a newly developed right ischiorectal fossa (IRF) nodule along with newly developed porta hepatis lymph node. PET scan showed uptake in these two new lesions. Therefore, the patient underwent resection of the primary tumor, porta hepatis lymph node and right ischiorectal fossa nodule excision. The histopathology of the primary tumor came as moderately differentiated adenocarcinoma with both ischiorectal lesion and the porta hepatis nodule being positive for metastatic disease.

Clinical discussion & conclusion

Ischiorectal fossa tumors are extremely rare with the majority being benign in origin. Nevertheless, the possibility of metastasis is there with no clear explanation regarding the pathway of how the metastatic cells can reach the IRF. Pre-operative diagnosis is important to determine the appropriate approach particularly if the mass is thought to be malignant. Further larger studies are needed to understand the pathway of metastasis to IRF.

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Colorectal cancer is one of the most common malignancies worldwide.

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Colorectal cancer has a tendency to metastasize to certain locations like local lymph nodes, liver and lungs.

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However, the ischiorectal fossa is an extremely rare location for metastatic tumors with vast majority being benign tumors.

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The ischiorectal fossa hasn't been reported before to be one of the sites of colon cancer metastasis.

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The exact pathway of metastasis to the ischiorectal fossa remains unknown.