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 Table of Contents  
CASE REPORT
Year : 2020  |  Volume : 3  |  Issue : 1  |  Page : 22-25

Diagnostic duplicity of spindle cell sarcoma: Stitch in time saves nine


1 Department of Orthopaedics, PGIMER, Chandigarh, India
2 Department of Surgery, PGIMER, Chandigarh, India

Date of Submission15-Jan-2020
Date of Decision26-Feb-2020
Date of Acceptance26-Feb-2020
Date of Web Publication30-Apr-2020

Correspondence Address:
Vishal Kumar
Department of Orthopaedics, PGIMER, Chandigarh - 160 012
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/JODP.JODP_4_20

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  Abstract 


The prime cause of low backache with radiculopathy is prolapsed intervertebral disc, but in conditions where the radiology and scans of the lumbosacral spine are insignificant and the symptoms are progressive, it can be a tumor involving the sciatic nerve. Here, we present a case of a 26-year-old female managed conservatively for her low backache with radiculopathy which ultimately turned out to be an undifferentiated malignant nerve sheath tumor of the sciatic nerve. It is one of the largest nerve sheath tumors reported in the literature. Combined transabdominal and Kocher–Langenbeck approaches were used to resect the tumor. Histopathology confirmed the diagnosis of the undifferentiated malignant nerve sheath tumor. Through this case report, we emphasize to screen the pelvis early if symptoms of sciatica are progressive along with insignificant scans of the spine.

Keywords: Nerve sheath tumor, prolapsed intervertebral disc, radiculopathy


How to cite this article:
Salaria AK, Kumar V, Savlania A, Dhatt SS. Diagnostic duplicity of spindle cell sarcoma: Stitch in time saves nine. J Orthop Dis Traumatol 2020;3:22-5

How to cite this URL:
Salaria AK, Kumar V, Savlania A, Dhatt SS. Diagnostic duplicity of spindle cell sarcoma: Stitch in time saves nine. J Orthop Dis Traumatol [serial online] 2020 [cited 2020 Jul 15];3:22-5. Available from: http://www.jodt.org/text.asp?2020/3/1/22/283680




  Introduction Top


The prime cause of pain, sensory, and motor symptoms in the distribution of the sciatic nerve is prolapsed intervertebral disc, but in rare instances, it can be a treacherous tumor involving the sciatic nerve as well, particularly if the symptoms are progressive and do not respond to the conventional treatment modalities along with insignificant and dubious scans of the lumbosacral spine lacking the clinicoradiological correlation.


  Case Report Top


We present a case of a 26-year-old female complaining of chronic low backache along with radicular symptoms in the distribution of the sciatic nerve for the past 6 months on the right side. The symptoms did not improve with the conventional nonsteroidal anti-inflammatory drugs and physiotherapy regimens, and the patient developed foot drop and progressively the bowel and bladder started getting involved. Interestingly, the patient had a history of backache with a bull hitting her at the lower back about 2 years before she presented to us. She and her family members related the symptoms to the bull hit and deferred clinical visits till she did not get relief with the conventional symptomatic management with analgesics, physiotherapy, etc., and off late started having gradual involvement of her bladder and bowel along with the right foot drop in the past 6 months. The patient presented to us at this stage. Review of her previous magnetic resonance imaging (MRI) and radiology of the lumbosacral spine did not reveal any large herniated disc.

Investigations

MRI of the pelvis was done, and it showed a large well-defined heterogeneously enhancing lesion with multiple locules of hemorrhage measuring 7.4 cm × 10.1 cm × 8.5 cm (AP * TR * CC) on the right hemipelvis extending along the greater sciatic foramen. The lesion was displacing the uterus and the anterior rectum laterally. The right-sided sacral ala showed altered signal intensity with cortical irregularity. The right sciatic nerve was found to be severely compressed and gulped around by the lesion at the level of greater sciatic foramen and not separately visualized from the lesion. Distally, the gluteal region was thickened and appeared hyperintense on T2. There was no encasement/infiltration of major iliofemoral vessels by the tumor [Figure 1]. Possibility of a neurogenic tumor was kept, and ultrasound-guided fine-needle aspiration cytology was done and it confirmed the presence of the malignant peripheral nerve sheath tumor. There were no significant findings on the MRI of the lumbosacral spine. The case was discussed in the multidisciplinary committee meeting comprising orthopedic surgeon, gastroenterology surgeon, vascular surgeon, general surgeon, and anesthetist. It was decided to resect the tumor. For better evaluation of the blood supply of the lesion, computed tomography (CT) angiography was done [Figure 2]. It revealed the presence of multiple arterial feeders from the right internal iliac artery and its branches. As the lesion was found to be vascular, it was decided to angioembolize it preoperatively with an intent to reduce the blood loss during surgery.
Figure 1: Magnetic resonance imaging pelvis showing large heterogeneous enhancing mass lesion the extending to the sacral foramen and involving sciatic nerve on the right side

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Figure 2: Computed tomography angiography showing multiple arterial feeders from the right internal iliac artery and its branches

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Treatment

Catheter diagnostic run of bilateral internal iliac vessels showed abnormal blush from the right internal iliac artery. Abnormal blush was embolized with polyvinyl alcohol and gelfoam slurry. Check angiogram showed no abnormal blush. The patient was taken into the operation theater 48-h postangioembolization. Since the tumor was dumbbell shaped extending from the pelvis through the greater sciatic foramen to the gluteal region, it was planned to remove the lesion through the combined transabdominal route and through the Kocher–Langenbeck approach [Figure 3]. The first midline laparotomy incision was given, and the tumor was approached from the anterior aspect. It was not found to be adherent to any visceral or pelvic organs but was exerting significant pressure on the adjacent viscera. Blunt dissection was done to separate the tumor capsule from the surrounding structures with simultaneous ligature of the feeding vessels. The posterior extension of the tumor into the gluteal region through the greater sciatic foramen limited its extraction anteriorly. Hence, the Kocher–Langenbeck approach was used to expose the tumor posteriorly too. It was freed from the posterior structures by blunt dissection, and then, it was pushed from the posterior aspect through the greater sciatic foramen facilitating its extraction anteriorly. The tumor was removed en bloc with no intraoperative spillage, and the specimen was sent for biopsy. Macroscopically, the tumor mass was encapsulated, and the outer surface showed the lobulated and irregular appearance. The cut section showed a variegated appearance with predominantly necrotic areas [Figure 4]. Microscopy showed an encapsulated, highly cellular tumor with intervening large areas of necrosis and hemorrhage. The tumor showed a fascicular arrangement. It contained moderate to markedly pleomorphic oval to elongated vesicular nuclei with conspicuous nucleoli and moderate eosinophilic cytoplasm. Mitosis was found to be brisk. Areas of myxoid and cartilage differentiation were evident; however, no osteoid elements were there. On immunohistochemistry, the tumor cells were positive for smooth muscle actin (SMA) while negative for S100p, myogenin, desmin, Vimentin, and CD34. Histopathology initially pointed toward a diagnosis of leiomyosarcoma until again a detailed discussion between the pathologist, radiologist, and surgeons commensurate with the detailed and further immunohistochemistry testing. On performing a further panel of immunohistochemistry, the tumor cells show focal weak positivity for CD56 and strong nuclear positivity for SATB2 [Figure 5]. Hence, based on the clinical data, radiological findings and histopathology features were found to be consistent with malignant peripheral nerve sheath tumor (weak CD56 positivity) with dedifferentiation toward smooth muscle (SMA positive) and chondro-osseous elements (presence of cartilage and SATB2 positive) [Figure 5]. The immediate postoperative period was uneventful. Incision sites healed well. Bowel and bladder training exercises were initiated. Ankle–foot orthosis was given for foot drop.
Figure 3: Combined transabdominal (a) and Kocher–Langenbeck approach (b) used in tumor resection

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Figure 4: (a and b) Dimensions of the resected tumor (13 cm × 6 cm × 6 cm). (c) The cut surface with variegated appearance and necrotic areas

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Figure 5: (a) Histopathology of resected tumor mass showing spindle cell proliferation with interspersed highly pleomorphic large cells. (b) The tumor cells show focal weak positivity for CD56. (c) On immunohistochemistry, the tumor cells are positive for smooth muscle antigen. (d) Strong nuclear positivity for SATB2

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Outcome and follow-up

To prevent the tumor recurrence, the patient is also being followed up by the oncologists. The patient is under close follow-up to monitor the neurological recovery and the bowel and the bladder functions.


  Discussion Top


Sarcomas are broadly classified on the basis of the originating tissue. Broadly, there are two categories of sarcomas: bone sarcomas and soft-tissue sarcomas, each having multiple subtypes.[1],[2],[3] Malignant peripheral nerve sheath tumor is a soft-tissue sarcoma originating in the connective tissue surrounding the nerves. About 50% of the cases are found in the patients of neurofibromatosis.[4] They may originate from a major or minor peripheral nerve or its sheath, with an incidence of 1 in 100,000. Signs and symptoms depend on the location and may range from mass effects to neurological symptoms. Etiology has been attributed to genetics with mutation of the chromosome 17 and p53 tumor suppressor gene. Diagnosis is based on the clinical features, CT scan, MRI, and positron emission tomographic scan and on the biopsy. Even with biopsy, the exact diagnosis is difficult due to its similarity to other spindle cell sarcomas. In fact, it is a type of spindle cell sarcoma with differentiation toward the neural elements based on immunohistochemistry.[5] Treatment is generally wide resection in combination with radiation therapy. In general, this rare variety of sarcoma has a poor prognosis with lung metastasis occurring in about 40% of the patients. Tumors >5 cm in size, high mitotic index, metastasis, and coexistent neurofibromatosis are poor prognostic indicators.[6],[7] Unresectable tumors due to its location or distant metastasis are amenable to chemotherapy although with an unpredictable response. The local and distant recurrence rate ranges from 40% to 70%, with a mere 5-year survival rate of 16%–52% only.[8],[9],[10]

On analyzing the clinical features of our case in detail and in toto, we found that it is very much plausible to misdiagnose the case and falsely attribute the neurological symptoms to a prolapsed intervertebral disc. There should be a high index of suspicion if the symptoms are progressive, and radiological examination of the spine is insignificant. Pelvis, sciatic nerve, and common peroneal nerve should be thoroughly evaluated by clinical examination, MRI, and nerve conduction studies. In our patient, when the radiology of the spine was inconclusive, we proceeded with the MRI of the pelvis which revealed this rare entity as a huge presacral mass encompassing the sacral plexus and the sciatic nerve. The mass extended right from the presacral area and exited from the greater sciatic foramen into the gluteal region following the sciatic nerve. Here, through this case, we emphasize to screen the pelvis and the sciatic nerve if the symptoms of sciatica are progressive with normal or insignificant radiology of the spine so that it can be detected early as tumor size is exponentially associated with worse prognosis. In such a large lesion, it is also difficult to comment on the origin of the tumor. Malignant peripheral nerve sheath tumor should always be kept as a differential diagnosis besides other soft-tissue sarcomas such as leiomyosarcoma, rhabdomyosarcoma, fibrosarcoma, and liposarcoma in scenarios simulating this index case. Critical analysis of the extent of the tumor is also very important to determine the surgical approach. Due to the large size of the tumor, we have to choose the combined anterior and posterior approaches with an aim to remove the tumor completely. To the best of our knowledge and literature search, this is one of the largest reported malignant peripheral nerve sheath tumors of the sciatic nerve. A detailed descriptive critical analysis of the resected tumor can reveal the correct diagnosis and differentiate it from other soft-tissue spindle cell sarcomas. Further research is warranted for the early and accurate diagnosis as well as optimal management of this rare soft-tissue sarcoma variant. A better understanding of genetics and molecular biology of such a tumor is equally warranted.

Learning points

  1. Gradually progressive radiculopathy with neurological symptoms in the presence of normal radiology of the spine should be taken seriously
  2. Malignant peripheral nerve sheath tumors can reach a huge size before being discovered
  3. MRI pelvis, CT scan, and nerve conduction studies are more than recommended in early diagnosis and delineating the size, origin, and the extent of the tumor
  4. The rate of local recurrence and pulmonary metastasis is quiet high.


Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
  References Top

1.
Yang J, Ren Z, Du X, Hao M, Zhou W. The role of mesenchymal stem/progenitor cells in sarcoma: Update and dispute. Stem Cell Investig 2014;1:18.  Back to cited text no. 1
    
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DeVita VT, Lawrence TS, Rosenberg SA. DeVita, Hellman, and Rosenberg's cancer: Principles & practice of oncology: Tenth edition. Wolters Kluwer Health Adis (ESP); 2015. p. 1241-313.  Back to cited text no. 3
    
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Evans DG, Baser ME, McGaughran J, Sharif S, Howard E, Moran A. Malignant peripheral nerve sheath tumours in neurofibromatosis 1. J Med Genet 2002;39:311-4.  Back to cited text no. 4
    
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Trojani M, Contesso G, Coindre JM, Rouesse J, Bui NB, de Mascarel A, et al. Soft-tissue sarcomas of adults; study of pathological prognostic variables and definition of a histopathological grading system. Int J Cancer 1984;33:37-42.  Back to cited text no. 5
    
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Panigrahi S, Mishra SS, Das S, Dhir MK. Primary malignant peripheral nerve sheath tumor at unusual location. J Neurosci Rural Pract 2013;4:S83-6.  Back to cited text no. 6
    
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Neville H, Corpron C, Blakely ML, Andrassy R. Pediatric neurofibrosarcoma. J Pediatr Surg 2003;38:343-6.  Back to cited text no. 7
    
8.
Hruban RH, Shiu MH, Senie RT, Woodruff JM. Malignant peripheral nerve sheath tumors of the buttock and lower extremity. A study of 43 cases. Cancer 1990;66:1253-65.  Back to cited text no. 8
    
9.
Kourea HP, Bilsky MH, Leung DH, Lewis JJ, Woodruff JM. Subdiaphragmatic and intrathoracic paraspinal malignant peripheral nerve sheath tumors: A clinicopathologic study of 25 patients and 26 tumors. Cancer 1998;82:2191-203.  Back to cited text no. 9
    
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Wong WW, Hirose T, Scheithauer BW, Schild SE, Gunderson LL. Malignant peripheral nerve sheath tumor: Analysis of treatment outcome. Int J Radiat Oncol Biol Phys 1998;42:351-60.  Back to cited text no. 10
    


    Figures

  [Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]



 

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