Int J Colorectal Dis (2014) 29:1587–1588 DOI 10.1007/s00384-014-1954-3
LETTER TO THE EDITOR
Mucosal Schwann cell hamartoma: just benign or more? Jagpal S. Klair & Mohit Girotra & Abhishek Agarwal & Farshad Aduli
Accepted: 29 June 2014 / Published online: 13 July 2014 # Springer-Verlag Berlin Heidelberg 2014
Dear Editor: Earlier grouped together under a common term neuromas or neurofibromas, “mucosal Schwann cell hamartoma” (MSCH) is a distinct subset of neural polyps whose significance is still undefined. MSCH currently is considered to have no association with any inherited disorder, and we wish to discuss its differentiating features from various other neural lesions of the GI tract. A 78-year-old Caucasian woman presented to the GI clinic for an evaluation of abdominal pain and intermittent tenesmus of several years. She had rectal cancer 15 years ago treated with a wide local excision with chemoradiotherapy, and the course was complicated by chronic radiation proctitis with partial response to topical rectal hydrocortisone. There was no personal or family history of multiple endocrine neoplasia (MEN) type 2B, neurofibromatosis (NF) type I, or Cowden syndrome. Her exam was remarkable for tenderness in the left lower abdomen. Colonoscopy revealed a 5-mm polyp (tubular adenoma) in the ascending colon and a 7-mm rectal polyp along with rectal erythema and inflammation, without erosions or ulceration. Histopathology of rectal polyp with hematoxylin and eosin (H&E) showed poorly circumscribed, homogeneously appearing lesion and diffuse proliferation of spindle-shaped cells with dense eosinophilic cytoplasm. The cells showed no premalignant changes, and immunostaining revealed strong positivity for S-100; rare axons highlighted J. S. Klair : M. Girotra : A. Agarwal : F. Aduli Department of Internal Medicine, University of Arkansas for Medical Sciences, Little Rock, AR, USA J. S. Klair : M. Girotra : A. Agarwal : F. Aduli (*) Division of Gastroenterology and Hepatology, Department of Medicine, University of Arkansas for Medical Sciences, 4301 W. Markham Street, Mailslot # 567, Shorey S8-68, Little Rock, AR 72205, USA e-mail: [email protected]
with neurofilament protein (NFP) and negative staining for glial fibrillary acidic protein (GFAP), epithelial membrane antigen (EMA), claudin-1, CD34, smooth muscle actin (SMA), and c-KIT [1, 4], overall consistent with a MSCH. The differential diagnosis of neural polyps comprise gastrointestinal stromal tumors (GISTs) in patients with neurofibromatosis type I (NF1), mucosal neuromas associated with MEN 2B, ganglioneuromas associated with Cowden syndrome, schwannomas, and intramucosal perineuromas [2, 3]. The peculiar clinical and histological features present in each of them enable their differentiation from MSCH. GI neurofibromas are strongly associated with NF1 (up to 25 % cases) [1], have heterogeneous cells like Schwann cells, fibroblasts, perineural cells, and axons and immunohistochemistry for S-100 is uneven. GISTs are usually seen in the stomach or small intestine, but rarely in the colon, as subepithelial tumors which stain positive for CD117 [1, 3, 4]. NFP have scattered axons with a significant subset of CD34-positive stromal cells. Mucosal neuromas appear in almost 100 % of patients with MEN 2B [1, 2], usually on the lips and tongue, as small sessile nodules and histologically have hyperplastic bundles of nerve cells, often with thickened perineurium, and frequent presence of axons. Ganglioneuromas (ganglioneuromatous polyposis and diffuse ganglioneuromatosis) are also associated with inherited syndromes [2–4] and histologically have ganglion cells differentiating them from MSCH. GI schwannomas are uncommon lesions, with 90 % located in the stomach and rarely in the colon [4], and histologically, they are well circumscribed but non-capsulated, with characteristic peripheral lymphoid cuffs and Antoni-A and Antoni-B regions that are absent in MSCH [2]. Lastly, intramucosal perineuromas are frequently associated with hyperplastic crypts and are histologically characterized by ovoid cells, pale eosinophilic and fine stroma, and cells arranged in a whorled pattern. Immunohistochemistry shows a negative reaction for S-100,
1588
weak reaction for EMA, and a subset of perineuromas showing a weak reaction for claudin-1. MSCH usually occurs in middle-aged females as in our case. They are incidentally found during screening colonoscopy as sessile hyperplastic polyps, usually confined to the colorectal region, and the size usually ranges from 1 to 6 mm with only two cases reporting a size of 10 and 22 mm. MSCH is currently considered benign and has not been proven to be associated with inherited syndromes like NF1, MEN 2B, and Cowden, which lightens the stringent follow-up with such syndromes. Having said that, we still need to be careful when following this subtype of neural polyps, as they still might be a part of some inherited tumor syndrome currently undiscovered, like the other neuronal lesions, indicating a possible role of genetic counseling and long-term follow-up of these lesions. In conclusion, physicians need to remain cognizant of this entity. MSCH is a rare entity and believed to be benign with no proven association with any inherited disorder. However,
Int J Colorectal Dis (2014) 29:1587–1588
its clinical significance is yet not completely established; hence, a need for close and long-term follow-up might be of patient’s benefit, for they still might be part of some unknown inherited disorder. Conflict of interest None
References 1. Gibson JA, Hornick JL (2009) Mucosal Schwann cell “hamartoma”: clinicopathologic study of 26 neural colorectal polyps distinct from neurofibromas and mucosal neuromas. Am J Surg Pathol 33(5):781–787 2. Miettinen M, Shekitka KM, Sobin LH (2001) Schwannomas in the colon and rectum: a clinicopathologic and immunohistochemical study of 20 cases. Am J Surg Pathol 25:846–855 3. Pasquini P, Baiocchini A, Falasca L et al (2009) Mucosal Schwann cell “hamartoma”: a new entity? World J Gastroenterol 15:2287–2289 4. Rocco EG, Iannuzzi F, Dell’era A et al (2011) Schwann cell hamartoma: case report. BMC Gastroenterol 11(68):21663626
LETTER TO THE EDITOR
Mucosal Schwann cell hamartoma: just benign or more? Jagpal S. Klair & Mohit Girotra & Abhishek Agarwal & Farshad Aduli
Accepted: 29 June 2014 / Published online: 13 July 2014 # Springer-Verlag Berlin Heidelberg 2014
Dear Editor: Earlier grouped together under a common term neuromas or neurofibromas, “mucosal Schwann cell hamartoma” (MSCH) is a distinct subset of neural polyps whose significance is still undefined. MSCH currently is considered to have no association with any inherited disorder, and we wish to discuss its differentiating features from various other neural lesions of the GI tract. A 78-year-old Caucasian woman presented to the GI clinic for an evaluation of abdominal pain and intermittent tenesmus of several years. She had rectal cancer 15 years ago treated with a wide local excision with chemoradiotherapy, and the course was complicated by chronic radiation proctitis with partial response to topical rectal hydrocortisone. There was no personal or family history of multiple endocrine neoplasia (MEN) type 2B, neurofibromatosis (NF) type I, or Cowden syndrome. Her exam was remarkable for tenderness in the left lower abdomen. Colonoscopy revealed a 5-mm polyp (tubular adenoma) in the ascending colon and a 7-mm rectal polyp along with rectal erythema and inflammation, without erosions or ulceration. Histopathology of rectal polyp with hematoxylin and eosin (H&E) showed poorly circumscribed, homogeneously appearing lesion and diffuse proliferation of spindle-shaped cells with dense eosinophilic cytoplasm. The cells showed no premalignant changes, and immunostaining revealed strong positivity for S-100; rare axons highlighted J. S. Klair : M. Girotra : A. Agarwal : F. Aduli Department of Internal Medicine, University of Arkansas for Medical Sciences, Little Rock, AR, USA J. S. Klair : M. Girotra : A. Agarwal : F. Aduli (*) Division of Gastroenterology and Hepatology, Department of Medicine, University of Arkansas for Medical Sciences, 4301 W. Markham Street, Mailslot # 567, Shorey S8-68, Little Rock, AR 72205, USA e-mail: [email protected]
with neurofilament protein (NFP) and negative staining for glial fibrillary acidic protein (GFAP), epithelial membrane antigen (EMA), claudin-1, CD34, smooth muscle actin (SMA), and c-KIT [1, 4], overall consistent with a MSCH. The differential diagnosis of neural polyps comprise gastrointestinal stromal tumors (GISTs) in patients with neurofibromatosis type I (NF1), mucosal neuromas associated with MEN 2B, ganglioneuromas associated with Cowden syndrome, schwannomas, and intramucosal perineuromas [2, 3]. The peculiar clinical and histological features present in each of them enable their differentiation from MSCH. GI neurofibromas are strongly associated with NF1 (up to 25 % cases) [1], have heterogeneous cells like Schwann cells, fibroblasts, perineural cells, and axons and immunohistochemistry for S-100 is uneven. GISTs are usually seen in the stomach or small intestine, but rarely in the colon, as subepithelial tumors which stain positive for CD117 [1, 3, 4]. NFP have scattered axons with a significant subset of CD34-positive stromal cells. Mucosal neuromas appear in almost 100 % of patients with MEN 2B [1, 2], usually on the lips and tongue, as small sessile nodules and histologically have hyperplastic bundles of nerve cells, often with thickened perineurium, and frequent presence of axons. Ganglioneuromas (ganglioneuromatous polyposis and diffuse ganglioneuromatosis) are also associated with inherited syndromes [2–4] and histologically have ganglion cells differentiating them from MSCH. GI schwannomas are uncommon lesions, with 90 % located in the stomach and rarely in the colon [4], and histologically, they are well circumscribed but non-capsulated, with characteristic peripheral lymphoid cuffs and Antoni-A and Antoni-B regions that are absent in MSCH [2]. Lastly, intramucosal perineuromas are frequently associated with hyperplastic crypts and are histologically characterized by ovoid cells, pale eosinophilic and fine stroma, and cells arranged in a whorled pattern. Immunohistochemistry shows a negative reaction for S-100,
1588
weak reaction for EMA, and a subset of perineuromas showing a weak reaction for claudin-1. MSCH usually occurs in middle-aged females as in our case. They are incidentally found during screening colonoscopy as sessile hyperplastic polyps, usually confined to the colorectal region, and the size usually ranges from 1 to 6 mm with only two cases reporting a size of 10 and 22 mm. MSCH is currently considered benign and has not been proven to be associated with inherited syndromes like NF1, MEN 2B, and Cowden, which lightens the stringent follow-up with such syndromes. Having said that, we still need to be careful when following this subtype of neural polyps, as they still might be a part of some inherited tumor syndrome currently undiscovered, like the other neuronal lesions, indicating a possible role of genetic counseling and long-term follow-up of these lesions. In conclusion, physicians need to remain cognizant of this entity. MSCH is a rare entity and believed to be benign with no proven association with any inherited disorder. However,
Int J Colorectal Dis (2014) 29:1587–1588
its clinical significance is yet not completely established; hence, a need for close and long-term follow-up might be of patient’s benefit, for they still might be part of some unknown inherited disorder. Conflict of interest None
References 1. Gibson JA, Hornick JL (2009) Mucosal Schwann cell “hamartoma”: clinicopathologic study of 26 neural colorectal polyps distinct from neurofibromas and mucosal neuromas. Am J Surg Pathol 33(5):781–787 2. Miettinen M, Shekitka KM, Sobin LH (2001) Schwannomas in the colon and rectum: a clinicopathologic and immunohistochemical study of 20 cases. Am J Surg Pathol 25:846–855 3. Pasquini P, Baiocchini A, Falasca L et al (2009) Mucosal Schwann cell “hamartoma”: a new entity? World J Gastroenterol 15:2287–2289 4. Rocco EG, Iannuzzi F, Dell’era A et al (2011) Schwann cell hamartoma: case report. BMC Gastroenterol 11(68):21663626
