Complete resection of adult prostatic rhabdomyosarcoma with 3D video and printing model: A case report and literature review

1 Introduction

Prostate sarcoma is an extremely rare and aggressive malignant tumor derived from stromal tissue of prostate gland with unfavorable prognosis [1]. The median overall survival is reported to be 2– 4 years and they tend to recur as well as metastasize to the liver and the lungs [2]. Prostate sarcoma was mainly divided into prostate leiomyosarcoma, rhabdomyosarcoma, fibrosarcoma and spindle cell sarcoma based on different histological features, and only less than 0.2% of all primary prostate tumor is diagnosed as prostatic rhabdomyosarcoma (RMS) in adults patients [3, 4].

In clinical practice, images in 2D pattern are often used to represent 3D tumor tissue in vivo, which limits the cognition on actual condition of the tumor [5]. Recent advances in medical imaging and radiology are helpful in the diagnosis, prognosis, and surgical development [5, 6]. Moreover, three-dimensional (3D) reconstructed images and video based on CT and MRI provide a more accurate and insightful approach for better evaluation in the surgical plan [7]. Further, the prevailing 3D printing technology pave a new path in medicine. Combination of radiology data and 3D printing can construct real-scale organ model and demonstrate different composition, just like organ in our body. With printed model, surgeons can feel and observe internal situation, so that they have confidence to challenge surgeries which were previously impossible [8].

Here we reported a case of prostatic rhabdomyosarcoma in a 36-year-old man who was considered to be alive less than 6 months according to our experience before. Fortunately, 3D reconstructed video and 3D printing model were applied to develop a more accurate and personalized way for this young man. Finally, a routine laparoscopic radical prostatectomy was performed to remove the huge prostatic mass completely with negative margin.

2 Case report

A 36-year-old male patient was admitted to our hospital due to intermittent gross hematuria and low urinary tract symptoms (LUTS) for more than one month before admission. The patient had no pain, fever or other symptoms. Digital rectal examination revealed a III ° enlarged mass arising from left lobe of prostate gland. Serum prostate specific antigen (PSA) level was normal at 3.69 ng/ml. Erythrocyte count of urinalysis was 968.9/uL, above the normal level 0– 14/uL.

Abdominal ultrasound indicated a heterogeneous large mass in prostate. Computed tomography (CT) and magnetic resonance imaging (MRI) scan of pelvis revealed a 9.6*5.3*7.6 cm tumor in the left lobe of prostate and the peri-prostatic fat was clear and complete (Fig. 1). The CT scan also showed enlarged lymph nodes at the right wall of the pelvis and multiple small lymph node on both sides of groins. Chest/abdominal CT scan and isotope bone scan indicated no evidence of distant metastasis. Furthermore, the patient underwent a transrectal ultrasound scan (TRUS) guided prostate biopsy and histopathological examination showed spindle-shaped cell tumor which revealed a suspect diagnosis of prostate sarcoma.

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Fig.1

Illustration of the imaging features of the neoplasm, which include Computed Tomography scan (A), T1-weighted MRI imaging (B), T2-weighed MRI imaging (C, D) of the neoplasm; coronal (E) and sagittal (F) plane T2-weighed MRI scan images.

We reconstructed and printed a 3D tumor model with the CT/MRI images and data by 16.0 Mimics software (Fig. 2, 3). From the 3D model, we can clearly see a huge mass originated from prostate behind bladder, the adjacent organs and tissues, like ureters of both sides, iliac arteries and pelvis.

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Fig.2

Images (A, B, C) and printed model (D) of CT/MRI 3D reconstruction, which show (1) a large mass in the prostate gland (blue in A,B,C and white in D); (2) Bladder (brown in A,B,C and yellow in D); (3) ureters of both sides (brown in A,B,C and dark orange in D).

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Fig.3

3D reconstruction dynamic video based on CT/MRI data including the enlarged prostate (blue), bladder and ureters (brown), kidneys (crimson), and iliac vessels (red).

The patient underwent a laparoscopic radical prostatectomy and extended lymphadenectomy after evaluating the surgery risk based on the anatomic structure. The enlarged prostate (9.6*5.3*7.6 cm), seminal vesicles, obturator and iliac fossa lymph nodes were completely removed with no-injury to bladder, ureters and neighboring vessels and tissues, and no obvious surgical complications was observed.

The histopathological result of specimen indicated a prostatic embryonal rhabdomyosarcoma with negative surgery margin and one right iliac lymph node metastasis. Immunohistochemical staining showed that the tumor was immune-positive in MyoD1, Myogenin, CD56, CD34, and it was negative in Des, EMA, SMA, S100, PCK, CgA, DOG-1 and CD117. The positive rate of Ki-67 was approximately 20% (Fig. 4).

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Fig.4

Macroscopic and microscopic histopathological features of prostatic rhabdomyosarcoma, which include gross view of completely-resected prostatic RMS and the tumor size is 9.6*5.3*7.6 cm (A). Spindled and fusiform shaped cells can be observed by hematoxylin and eosin stain (B); the tumor cells were immune-positive in MyoD1 (C), Myogenin (D), CD56 (E) and CD34 (F).

The patient accepted adjuvant chemotherapy consisted of ifosfamide and epirubicin at 1 month after surgery to prevent tumor recurrence. After an 18-month follow-up, the patient was alive with no malignant progression and no severe postoperative complication associated with surgery.

Prostatic sarcoma is a rare mesenchymal tumor originated from prostate, and rhabdomyosarcoma is a main subtype of soft-tissue sarcoma which occurs largely in the pediatric patients, only rare cases are described in adults [9, 10]. Rhabdomyosarcoma in adults has more malignant potential and likely to has poorer response to treatment, comparing with that in children [11, 12]. Microscopic examination of prostatic RMS tends to be morphological heterogeneity. Typical feature of neoplastic cells is spindled, and fusiform or rounded cells can also be seen in well-developed RMS. Diagnosis of rhabdomyosarcoma should be considered when a spindle cell proliferation is encountered on biopsy, particularly in young patients [3, 11]. Positive immunohistochemistry staining in Myogenin and MyoD1 indicate skeletal muscle differentiation of the tumor, which are the biomarkers for the diagnosis of RMS [2, 13].

There is no consensus on the best therapeutic approach for prostate RMS so far, and surgery with or without chemotherapy and radiotherapy appears to be the primary treatment for prostate sarcoma [10, 14]. Here, we summarized the previous reported prostate RMS cases who underwent prostatectomy [12, 15– 19] (Table 1). Several historic prostate sarcoma cohort studies revealed that complete surgical resection of sarcoma offered a better chance for cure and prolonged overall survival [20–22]. For the patients with metastases at diagnosis, multimodality approach including chemotherapy (variation of VAC, vincristine, actinomycin, cyclophosphamide) and local radiation therapy (XRT) could help in achieving better prognosis [9].

However, due to the large average size and infiltrative tendency of malignancy, it is relatively difficult to completely resect the tumor [23]. To make appropriate surgical plan, we need to obtain precise and detailed image information about the size, number, location of the tumor and the adhesion status between the tumor and the adjacent organs, vascular distribution and metastasis before surgery. It is challenging to remove the large RMS neoplasm completely in a limited space avoiding the injury of surrounding tissues and organs, especially for laparoscopic radical prostatectomy surgery [2]. In this case, extirpative surgery had the best chance to prevent recurrence and spread of cancer cells. 3D reconstruction of CT/MRI data is a mature technology which has been applied in many kinds of surgeries, including adrenal surgery [7], meningioma resection [24], and hepatectomy [25]. With the aid of 3D model, appropriate surgery plan was made by evaluating the accurate status of tumor and surrounding structures, and the neoplasm was removed completely with negative surgery margin. 3D dynamic videos can also be applied to help people like patients’ relatives who do not have medical background in understanding the procedures of surgeries.

Prostatic rhabdomyosarcoma is a subtype of prostate sarcoma which is rare and highly aggressive in adults. Though, there is no standard therapeutic approach for prostate sarcoma generally, tumor resection surgery appears to be the mainstream treatment. In this case, a large prostatic RMS was entirely removed with the help of CT/MRI data 3D reconstruction, indicating 3D reconstruction technology can be a promising assistive tool for laparoscopic radical prostatectomy.