Plexiform schwannoma of the rectum

Challenging Management of Plexiform Schwannoma and Plexiform Neurofibroma

ABSTRACT

Plexiform variants of neurofibromas and schwannomas are rare and typically arise in superficial soft tissues in the head and neck region. The treatment of these tumors is challenging and no generally accepted guidelines exist for their optimal management. The purpose of this study was to review the management and long-term prognosis of head and neck plexiform neurofibromas and schwannomas at 2 tertiary care academic hospitals in Finland over a 31-year period. The pathology files were searched for plexiform neurofibromas and schwannomas between the years 1990 and 2020. The case notes were reviewed for full management details. Two plexiform schwannomas and 6 plexiform neurofibromas were identified. Five of the 6 plexiform neurofibromas were managed operatively. All patients with a surgically managed plexiform neurofibroma underwent multiple operations. Sclerotherapy abolished 1 patient's cutaneous plexiform neurofibromas. The management of plexiform neurofibromas and plexiform schwannomas remains challenging. Sclerotherapy may offer a promising management option for cutaneous plexiform neurofibromas.

Visceral plexiform schwannoma: A case series

Plexiform schwannoma (PS) is a benign tumour of the peripheral nerve sheath that is typically found in the skin. Fewer than 15 cases of visceral PS have been reported to date in both adults and children. We herein discuss a series of 3 patients (2 male and 1 female) with abdominal PS, aged 10-16 years (mean age, 12 years). All the patients had an acute presentation with abdominal pain, which was associated with rectal bleeding in 1 case and with walking difficulties in 1 case. Radiological investigations included abdominal magnetic resonance imaging (MRI) and computed tomography, along with neurofibromatosis screening (cerebral MRI and dermatological evaluation). Complete removal of the mass was possible in 2 of the patients (in 1 case by laparoscopically assisted surgery). Follow-up was uneventful. Abdominal PS is a rare occurrence. Due to its possible association with neurofibromatosis, the diagnosis of PS should prompt an investigation for other manifestations of this disorder.

Intestinal Schwannoma: A Clinicopathological, Immunohistochemical, and Prognostic Study of 9 Cases

Background

Intestinal schwannoma is a type of intestinal interstitial tumor with a very low incidence. At present, there are few studies on intestinal schwannoma.

Methods

From January 2010 to January 2018, the patients diagnosed with intestinal schwannoma at the China-Japan Union Hospital of Jilin University were retrospectively reviewed. The patients' clinicopathological features and prognosis were analyzed.

Results

This study enrolled 9 patients with intestinal schwannoma, including 3 males and 6 females. The main symptoms of the patients were abdominal pain and melena. Abdominal computed tomography showed intussusception, slightly high-density shadowing in the intestine, thickening of the intestinal wall, and an intestinal mass. Colonoscopy and endoscopic ultrasonography showed submucosal masses without ulcer formation. Two patients underwent endoscopic biopsy, and the pathological results revealed inflammation and necrosis. One patient had increased neuron-specific enolase (NSE) levels. Immunohistochemical analysis showed that the tumor cells were positive for S-100 and negative for CD117, DOG-1, desmin, and smooth muscle actin. An average of 17 lymph nodes were found around the intestines in 4 patients, all of which demonstrated reactive hyperplasia. No recurrence or metastasis occurred during postoperative follow-up.

Conclusions

Intestinal schwannoma is a rare tumor, and in our study its incidence was higher in women than in men. The main symptoms were abdominal pain and melena. Preoperative increases in NSE levels might contribute to a diagnosis. Complete surgical resection with free negative margins is the standard treatment for benign schwannoma. There was no recurrence or metastasis after complete surgical resection, suggesting that follow-up may not be required.

Schwannoma of the colon and rectum: a systematic literature review

Background

Schwannomas of the colon and rectum are rare among gastrointestinal schwannomas. They are usually discovered incidentally as a submucosal mass on routine colonoscopy and diagnosed on pathologic examination of the operative specimen. Little information exists on the diagnosis and management of this rare entity.

The aim of this study is to report a case of cecal schwannoma and the results of a systematic review of colorectal schwannoma in the literature.

Main body

PubMed, Scopus, and Cochrane database searches were performed for case reports and case series of colonic and rectal schwannoma.

Ninety-five patients with colonic or rectal schwannoma from 70 articles were included. Median age was 61.5 years (59% female). Presentation was asymptomatic (28%), rectorrhagia (23.2%), or abdominal pain (15.8%). Schwannoma occurred in the left and sigmoid colon in 36.8%, in the cecum and right colon in 30.5%, and in the rectum in 21.1%. Median tumor size was 3 cm and 56.2% of patients who underwent preoperative colonoscopy had a typical smooth submucosal mass. At pathology, 97.9, 13.7, and 5.3% of schwannomas stained positive for S100, vimentin, and GFAP, respectively. The median mitotic index was 1/50.

Conclusions

Colorectal schwannoma is a very rare subtype of gastrointestinal schwannoma which occurs in the elderly, almost equally in men and women. Schwannoma should be included in the differential diagnosis of a submucosal lesion along with gastrointestinal stromal tumor, neuro-endocrine tumors, and leiomyoma-leiomyosarcoma. Definitive diagnosis is based on immunohistochemistry of the operative specimen. Rarely malignant, surgery is the mainstay of treatment.

Magnetic resonance imaging findings for differential diagnosis of perianal plexiform schwannoma: Case report and review of the literature

Plexiform schwannoma is an extremely rare variant of schwannoma, accounting for approximately 5% of cases. Due to the rarity and lack of typical symptoms, signs and radiological images, a definite diagnosis of plexiform schwannoma may not be made by clinicians prior to biopsy. In the present study, we report the first case (to our knowledge) of perianal plexiform schwannoma arising from the overlapped skin of the ischioanal fossa, and we propose an intratumorally nonenhanced circumferential capsule dividing the tumour into multiple homogeneously enhanced nodules as a magnetic resonance imaging feature to aid in the differential diagnosis of plexiform schwannoma from ancient schwannoma, cavernous haemangioma, liposarcoma and plexiform neurofibroma.

Gastric plexiform schwannoma in association with neurofibromatosis type 2

Plexiform schwannoma (PS) is an uncommon variant of schwannoma characterized by a multinodular (plexiform) growth pattern. It comprises up to 5 % of all schwannomas. The association between PS and neurofibromatosis type 1 or type 2 (NF1/NF2) is only rarely reported. Most cases of PS occur in the skin and subcutaneous soft tissue, with only a few reports of digestive tract involvement. We describe an 18-year-old male with NF2 who had bilateral vestibular schwannomas and multiple cutaneous PSs, and a 3-year history of abdominal pain. The patient ultimately underwent a distal gastrectomy for a partially obstructing submucosal antral mass, associated with an overlying ulcer. Histopathologic examination showed the mass to be a PS. The patient is alive and well, without symptoms, 12 months postoperatively. A review of the English language medical literature yielded only ten examples of PS arising in the digestive tract. Our patient is the first to be reported to have a gastric PS, and only the second patient to be reported with a digestive tract PS to have NF2, and the only patient reported to have both digestive tract and cutaneous PSs. Despite its rare occurrence with NF2, the finding of PS at any site should stimulate an examination for other manifestations of this disorder.

CLINICAL TRIAL REGISTRATION

None.

Morphological spectrum of peripheral nerve sheath tumors: An insight into World Health Organization 2013 classification

Introduction:

Peripheral nerve sheath tumors (PNSTs) are neuroectodermal in origin. Now these tumors are classified under World Health Organization (WHO) classification of tumors of soft tissue and bone 2013.

Objective:

To study the morphological spectrum of PNST and to study the secondary degenerative changes associated with it.

Materials and Methods:

This study was conducted from January 2010 to June 2015. The gross details of tumor and patient's demographic profiles were reviewed. The hematoxylin and eosin stained slides were reassessed and the lesions were categorized and classified as per the WHO 2013 classification. The tumors were also assessed for secondary degenerative changes.

Results:

Our study comprised 143 cases of PNST. Age of the patients ranged from 5 to 75 years. 21–30 years is the most common age of occurrence with head and neck being the most common site. The PNSTs observed in the present study were neurofibroma (NF) (61.5%), schwannoma (36%), malignant PNST (2%), and granular cell tumor (0.5%). Nearly 10% of NF fulfilled the criteria for neurofibromatosis 1 (NF1). Rare tumors such as plexiform schwannoma and granular cell tumor were also observed. Malignant tumors were larger in dimension than benign. Myxoid, cystic, and hyaline changes were commonly associated with benign tumors while necrosis, hemorrhage, and mitotic activity were seen with malignant tumors.

Conclusion:

This series highlights the pathological variants of PNST along with their morphological changes and NF1 association. It is essential to be familiar with all these variants of PNST for accurate diagnosis as they have varied biological behavior.

The immunohistochemical profile of granular cell (Abrikossoff) tumor suggests an endomesenchymal origin

Granular cell tumor (GCT) is an uncommon soft tissue neoplasm which has an unclear histogenesis. The aim of this study was to analyze its immunophenotype and hypothesize on the histogenesis of GCT. A database of 2,250 soft tissue tumors was examined to identify and characterize the particularities of GCTs. A large panel of antibodies was used. Of the 2,250 tumors, only 15 were GCTs (0.66 %); these were diagnosed in patients whose average age was 37 years. Among them, 5 had malignant potential, the remaining 10 were benign. One of these benign tumors was associated with a metachronous chondrosarcoma with metastases in the lungs. No recurrences were reported in these cases. The benign tumors displayed positivity for S-100, neuron-specific enolase (NSE), CD56, epithelial membrane antigen (EMA), and inhibin. In the atypical GCTs, NSE, S-100 protein, c-KIT, RET and EMA were positive, while inhibin and CD56 were negative; rare osteoclastic-like histiocytes, marked by CD68, were seen. All cases were negative for CD31, CD34, smooth muscle actin, desmin, maspin, and calretinin. Ovoid bodies expressed CD105, synaptophysin, and HER-2. All the cases were microsatellite-stable tumors. The immunoprofile suggests that the GCT seems to have an endomesenchymal origin. The c-KIT and RET positivity, associated with microsatellite stability, and the immunoprofile of the ovoid bodies have never reported before in GCTs.