Comparative study of CT appearances in mucinous tubular and spindle cell carcinoma and collecting duct carcinoma of the kidney

Indolent mucinous tubular and spindle cell carcinoma of the kidney: A case report and review of the literature

Mucinous tubular and spindle cell carcinoma of the kidney (MTSCC) is a rare subtype of renal cancer. It consists of tubules separated by mucus stroma and a spindle cell. Few cases have been reported; thus, the imaging features of MTSCC are not well characterized. An MTSCC in the left kidney of a 65-year-old woman was incidentally discovered during a medical checkup. A review of the patient's medical history revealed that this kidney lump had an indolent growth process. The current study presented this case and reviewed the pathological features, imaging findings and treatment options of MTSCC to strengthen the recognition of this rare renal neoplasm by radiologists.

OUP accepted manuscript

Mucinous tubule and spindle cell carcinoma (MTSCC) of the kidney is a rare renal pleomorphic tumor considered as low-grade malignant, with occurring mainly in female. Few mucin-poor MTSCC cases have been reported so far. A typical MTSCC is composed of closely arranged tubules with pale mucus matrix and spindle cell components. Mucin-poor MTSCC is difficult to distinguish from other renal cell carcinomas due to small amount of mucus. We reported a case of mucin-poor MTSCC in a 37-year-old male with detailed imaging, histology, immunohistochemical and next-generation sequencing information, looking forward to providing an insight into mucin-poor MTSCC.

MR characteristics of mucinous tubular and spindle cell carcinoma (MTSCC) of the kidney: comparison with clear cell and papillary subtypes of renal cell carcinoma

PURPOSE

To describe MR features of mucinous tubular spindle cell carcinoma (MTSCC) of the kidney that may help differentiate from clear cell renal cell carcinoma (ccRCC) and papillary RCC (pRCC).

METHODS

15 MTSCCs were retrospectively evaluated by MR with T2-weighted image without fat suppression (n = 15) and dynamic contrast-enhanced (DCE), fat-suppressed T1-weighted GRE (n = 11). Size-matched ccRCC (n = 30) and pRCC (n = 30) were evaluated as control. T2 ratio was calculated as the signal intensity (SI) ratio of the lesion to the renal cortex on T2W images. Enhancement ratio (ER) was calculated as (SI_post - SI_pre)/(SI_pre), where SI_pre (SI_post) is the SI of the entire lesion on each phase of DCE images. Early nodular enhancement was subjectively evaluated in MTSCC. T2 ratio and ER were compared using the Mann-Whitney U test with Bonferroni correction.

RESULTS

The mean value of T2 ratio was highest in ccRCC (1.24), followed by MTSCC (1.02), and pRCC (0.84). Difference of T2 ratio was significant between ccRCC and pRCC (p < 0.001), but not between MTSCC and ccRCC (p = 0.4) or between MTSCC and pRCC (p = 0.2). The mean ER of MTSCC, ccRCC and pRCC were 1.33, 1.53 and 0.38 in corticomedullary phase (CMP), 1.60, 1.61 and 0.69 in nephrographic phase (NGP) and 1.79, 1.35 and 0.77 in excretory phase (EP), respectively. ERs were significantly different between MTSCC and pRCC in CMP (p = 0.01), NGP (p = 0.003), and EP (p = 0.002). Early nodular enhancement was observed in 4/11 MTSCC (36%), 17/30 ccRCC (57%), and 2/30 pRCC (7%).

CONCLUSIONS

MTSCC has distinct MR features that can help differentiate from ccRCC and pRCC. MTSCC enhances more avidly compared to pRCC and shows gradual progressive enhancement.

Mucinous tubular and spindle cell carcinoma of the kidney: Five case reports and review of the literature

Mucinous tubular and spindle cell carcinoma (MTSCC) of the kidney is a rare and polymorphic tumor, which has been previously considered to be a low-grade malignancy, predominantly occurring in women. To the best of our knowledge, MTSCC with bladder metastasis has never been reported. The current study presents five adult cases of MTSCC that included three male and two female patients. Among the male cases, two were of advanced stage, one with MTSCC and renal chromophobe cell carcinoma with bladder metastasis and the other with MTSCC with invasion of the renal vein. The other three cases with small masses were at an early stage. All five cases had a good prognosis and were without recurrence after several years of follow-up. A 70-year-old male with intermittent gross hematuria, intermittent renal colic, and groin radiation pain for a year (case 1), was incidentally detected to have a left renal density mass by total abdominal enhanced computed tomography scans. In the other four cases, renal masses were found by B-ultrasound. The patient in case 1 underwent a retroperitoneal laparoscopic radical nephroureterectomy with bladder cuff resection and transurethral resection of the bladder tumor, and received gemcitabine hydrochloride via intravesical instillation therapy plus cisplatin chemotherapy every 3 months. The patient in case 2 underwent an open left radical nephrectomy and renal pedicle lymph node dissection. The other three patients underwent a laparoscopic radical nephrectomy. All five patients had no recurrence or new metastasis in other organs after follow-up. In conclusion, the incidence of MTSCC in men and women is not as disparate as reported in previous publications. The characteristics of the images of the five adult cases in the present study showed a considerable consistency, with only minor differences. The malignancy and prognosis of MTSCC are still controversial, and thus inclusion and review of more cases is required to reach a definite final conclusion. Sunitinib and gemcitabine chemotherapy in combination with cisplatin may be effective for the therapy of MTSCC patients with metastasis, but a larger range of treatments needs to be identified.

Imaging of Unusual Renal Tumors

PURPOSE OF REVIEW

Renal masses are a wide entity and a common finding in clinical practice. Detection of these masses has increased in the last years, yet mortality rates have slightly decreased.

RECENT FINDINGS

According to the World Health Organization classification, there are 8 types, 51 subtypes, and a lot more subsequent subclassifications of renal tumors. Histopathological analysis should always be assessed for final diagnosis of theses tumors. However, imaging can be an important diagnostic guidance. The most common diagnoses of renal tumor are clear cell carcinoma, papillary renal cell carcinoma, angiomyolipoma, and transitional cell carcinoma. Nonetheless, a considerable variety of particular tumors can arise from the kidney, challenging the expertise of radiologists and urologists on this subject. The awareness of these unusual entities is vital for professionals working at a complex medical facility with greater volume of patients. We hereby present uncommon renal tumors and its pathological and radiological features.

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.