Mucinous tubular and spindle cell carcinoma of the kidney: the contrast-enhanced ultrasonography and CT features of six cases and review of the literature

A retrospective study of imaging characteristics of mucinous tubular and spindle cell carcinoma in the kidney

Purpose

To strengthen the recognition of mucinous tubular and spindle cell carcinomas of the kidney (MTSCC) by analyzing ultrasound and computed tomography findings.

Materials and methods

This study retrospectively enrolled eleven patients with pathologically confirmed mucinous tubular and spindle cell carcinomas from 2007 to 2022. The clinical, imaging, pathological features, and prognosis of all included patients were analyzed. All imaging features were evaluated in consensus by two genitourinary radiologists.

Results

All patients (48 ± 17 years, male to female, 3:8) presented with a solitary renal tumor with a mean diameter of 6.3 cm. Most of the lesions were located in the renal cortex. In ultrasonography, all 11 patients underwent conventional ultrasound and color Doppler flow imaging, and only three underwent contrast-enhanced ultrasound. In computed tomography (CT) examination, 8 of the 11 patients underwent plain CT and contrast-enhanced CT, and 1 patient underwent plain CT only. Grayscale ultrasound image demonstrated that most of the lesions were homogeneously hypoechoic with clear boundaries and regular shapes. Color Doppler flow imaging showed spotty blood flow in some cases. Contrast-enhanced ultrasound showed heterogeneous mild enhancement, and the contrast agent showed 'slow in and simultaneous/fast out' pattern. Plain CT showed equal or low density. CECT scanning showed slight heterogeneous enhancement in 6 patients, mild homogeneous enhancement in 2 patients. All lesions showed no hemorrhage, cystic degeneration or necrosis. Contrast-enhanced CT and contrast-enhanced ultrasound showed typical low-vascular tumors.

Conclusion

MTSCC are more common in middle-aged with a significant female preponderance. CT and ultrasound showed hypovascular tumors. Preoperative imaging diagnosis is difficult. It is necessary to distinguish from other hypovascular renal tumors.multimodal imaging may be helpful for preoperative diagnosis.

Mucinous tubular and spindle cell carcinoma of the kidney: a report of seven cases

OBJECTIVE

To further analyse the imaging features and tumour outcomes of mucinous tubular and spindle cell carcinoma (MTSCC) of the kidney.

MATERIALS AND METHODS

The current study retrospectively reviewed the clinical information of seven patients diagnosed with MTSCC at our institution from January 2011 to March 2023.

RESULTS

The median age at diagnosis was 52 years (range, 32-66 years) and the majority of patients were female (71.4%). On conventional abdominal ultrasound, the majority of the tumours (5/7) were heterogeneous hypoechoic or slightly hypoechoic. Colour Doppler flow imaging showed blood flow within the tumour in 2 cases and peripheral blood flow signal in 1 case. On non-enhanced CT, all tumours had a spherical or ovoid shape, with an expansile growth mode, and had clear or unclear boundaries with the surrounding renal parenchyma. The tumours were either partially exophytic (n = 4) or parenchymal (n = 3), while no cases of completely exophytic tumour was observed (n = 0). On contrast-enhanced CT, the majority of tumours (5/7) showed a heterogenous pattern of enhancement and the mean tumour diameter was 6.7 ± 4.4 cm (range, 2.1-16.8 cm). All patients underwent partial or radical nephrectomy for pT1a (42.9%), pT1b (28.5%), pT2 (14.3%) or pT3b (14.3%) stage. Among these, 1 patient (14.3%) had a level I tumour thrombus at diagnosis and died of disease 24.5 months later. The remaining patients had no recurrence or metastasis.

CONCLUSION

MTSCC is not universally indolent, which tends to occur in female patients of a broad range of ages. MTSCC is a hypovascular renal tumour, which is different from clear cell renal cell carcinoma (RCC); however, it is difficult to distinguish MTSCC from other hypovascular RCC subtypes because of the overlap of their imaging characteristics.

Mucinous Tubular and Spindle Cell Carcinoma of the Kidney: A Study of Clinical, Imaging Features and Treatment Outcomes

Purpose

To describe the clinical, imaging, pathological features and oncologic outcomes of mucinous tubular and spindle cell carcinoma (MTSCC) of the kidney.

Patients and Methods

Twenty-two cases of MTSCC were pathologically identified between January 2004 and April 2021 at our institution. The clinical and imaging findings, pathological features, treatment methods and outcomes of the patients were reviewed.

Results

These cases included 17 women and 5 men, with a median age at diagnosis of 52.5 years. On contrast-enhanced CT, MTSCC was less enhanced than the adjacent renal parenchyma. Tumor attenuation values were 33.3 ± 6.8HU, 44.0 ± 9.1HU, 54.4 ± 13.9HU and 67.1 ± 11.8HU in the non-contrast, corticomedullary, nephrographic and excretory phases of CT, respectively. Contrast-enhanced ultrasonography and MRI also showed hypovascular features of the masses. On MRI, the tumors were isointense on T1-weighted images and slightly hypo- or hyperintense on T2-weighted images. Diffusion-weighted imaging revealed a low apparent diffusion coefficient of the tumor. The patients were managed with laparoscopic partial nephrectomy (n=5), radical nephrectomy (n=16), or robotic-assisted laparoscopic partial nephrectomy (n=1). The median follow-up time was 59.5 months. All the patients were free of local recurrence or distant metastasis.

Conclusions

MTSCC is generally indolent and has favorable outcomes. The imaging features of MTSCC are generally hypovascular, which is significantly different from clear cell renal cell carcinoma. However, it is still difficult to distinguish MTSCC from other hypovascular renal tumors preoperatively because their imaging features overlap. Further studies are essential to fully characterize the features of this rare RCC variant.

Use of Contrast Ultrasound for Renal Mass Evaluation

An introduction to the expanding modality of contrast-enhanced ultrasound is provided, along with basics on contrast agents and technique. The contrast ultrasound findings of multiple renal tumors are reviewed with examples, including clear cell renal cell carcinoma, papillary renal cell carcinoma, chromophobe renal cell carcinoma, other rare renal cell carcinoma subtypes, oncocytoma, upper tract urothelial carcinoma, lymphoma, and angiomyolipoma, followed also by brief discussions of renal infections and pseudolesions.

Mucinous Tubular and Spindle Cell Carcinoma: A Review of Histopathology and Clinical and Prognostic Implications

Mucinous tubular and spindle cell carcinomas are rare kidney tumors with generally indolent behavior. As the name suggests, classic histomorphology reveals bland spindle cells, tubules, and mucinous stroma. Uncommon histologic features include mucin-poor stroma, high nuclear grade, cellular pleomorphism, and presence of necrosis. Rare cases can show aggressive growth and distant metastasis. Mucinous tubular and spindle cell carcinoma has characteristic chromosomal abnormalities and the molecular signature remains the same, irrespective of the varied histomorphology.

Huge mucinous tubular and spindle cell carcinoma of kidney: A rare case report and literature review

RATIONALE

Mucinous tubular and spindle cell carcinoma (MTSCC) is a variant of renal cell carcinoma newly added to the WHO classification in 2004. It is a rare variant of renal cell carcinoma and sometimes it is not easy to distinguish MTSCC from papillary renal cell carcinoma, chromophobe renal cell cancer, etc. The prognosis of MTSCC is favorable after surgical resection.

PATIENT CONCERNS

A 45-year-old male patient presented with a right renal mass that was detected on ultrasonography incidentally. The computed tomography scan showed a huge homogenous mass with patchy calcification in the central area, and the lesion was slightly enhanced after contrast injection.

DIAGNOSES

According to postoperative pathology, the patient was diagnosed with MTSCC.

INTERVENTIONS

The patient underwent an open transabdominal radical resection of right kidney and right retroperitoneal lymph node dissection.

OUTCOMES

The surgical outcomes were good, and no recurrence or metastasis was observed during the follow-up.

LESSONS

MTSCC is a rare malignancy of the kidney and the prognosis is usually favorable. Preoperative enhanced CT and MRI can help differentiate MTSCC from other renal tumors, so as to provide a more suitable surgical approach for those who need to retain renal function as much as possible.