Case Of Low-grade Appendiceal Mucinous Neoplasm Research Articles

Low-grade Appendiceal Mucinous Neoplasm: A Series of Four Cases

Low-grade Appendiceal Mucinous Neoplasm (LAMN) is a rare malignant neoplasm seen in less than 0.3% of appendectomy specimens. Patients with LAMN can present with abdominal pain, mimicking appendicitis clinically. In later stages, it can rupture, leading to Pseudomyxoma peritonei (PMP). Therefore, a high clinical suspicion is needed for correct diagnosis and management. The prognosis of LAMN depends on the presence or absence of mucin/neoplastic epithelium outside the appendix. For LAMN confined to the appendix, appendectomy alone is sufficient for management, with conservative follow-up. For LAMN with extruded acellular mucin localised to the appendiceal serosa, management involves appendectomy and PMP surveillance. For all mucinous lesions of the appendix, it is essential to submit the entire appendix for histopathologic examination, thoroughly evaluating the presence of mucin/neoplastic epithelium involving the serosa/extra appendiceal tissue for accurate staging and to predict the risk of recurrence and determine further management. Here four cases of LAMN due to their rarity and clinical importance is presented. This study of four cases emphasises that the clinical diagnosis of this rare malignancy is difficult, and radiological investigations were not available as these patients presented with clinical features mimicking appendicitis. Emergency appendectomy was performed in all cases. LAMN should be considered as a differential diagnosis because if not diagnosed and treated in the early stages, it can lead to dreaded complications like PMP. The histopathological examination of all four cases of LAMN showed dissecting acellular mucin in various stages of progression in the appendicular wall, but none involving the serosa. This highlights the importance of timely surgical intervention and histopathological examination for an exact diagnosis and staging of LAMN for further follow-up or treatment.

Low grade appendiceal mucinous neoplasm

Low grade appendiceal mucinous neoplasm (LAMN) is a rare tumour which lacks usual form of destructive invasion but has ability to spread to peritoneum and ovaries which frequently progresses to pseudomyxoma peritonei and often result in death of patient despite the bland histology of the mucinous epithelium. There are lot of controversies about its classification, clinical significance of pseudomyxoma peritonei, whether ovarian mucinous tumours in this setting are separate primaries or are the metastasis from the appendiceal tumours which are to be solved. We reported two cases of LAMN in which first case was with pseudomyxoma peritonei with secondary involvement of left ovary while other was simple LAMN without any involvement. Whenever we diagnosed LAMN it is necessary to look for ovarian involvement and pseudomyxoma peritonei.It is necessary to rule out ovarian involvement and pseudomyxoma peritonie whenever we diagnosed LAMN. The unified approach of grading pseudomyxoma peritonei is required for more standardized and prognostically valuable diagnostic reporting.

Clinicopathological analysis and surgical strategy of primary appendiceal neoplasms

Objective: To investigate the clinicopathological features, surgical methods and prognosis of primary appendiceal neoplasms. Methods: A descriptive case series study was performed. Clinical data of patients diagnosed with primary appendiceal neoplasms in Peking University First Hospital from 2006 to 2017 were retrospectively analyzed. Patients who underwent surgery and were confirmed as appendiceal neoplasms by postoperative pathology were included. Cases of cecal tumor invading the appendix and other organ tumors implanting in the appendix and cases of recurrent appendix tumors were excluded Pathological classification was based on the 4th edition of the WHO classification of digestive tract tumors (2010 edition), and the efficacy of operation methods of low grade appendiceal mucinous neoplasm (LAMN) were analyzed. Results: A total of 115 patients were enrolled, including 52 males and 63 females with a median age of 59 (51, 71) years. Clinical symptoms usually manifested as dormant pain in the right lower quadrant, migrating right lower abdominal pain, fever and bloating. Twenty-four cases were accidentally discovered during surgery, and 21 cases were found by physical examination. The preoperative diagnosis rate of CT and ultrasound was 40.2% (43/107) and 25.5% (24/94) respectively. The postoperative pathological types contained 83 cases of LAMN, 12 cases of mucinous adenocarcinoma, 9 cases of appendiceal neuroendocrine neoplasms (aNEN), 2 cases of mucinous adenocarcinoma with signet ring cells, 3 cases of serrated adenoma, 2 cases of goblet cell carcinoid, 2 cases of lymphoma, 1 case of leiomyoma and 1 case of schwannomas. All the patients underwent surgical resection, including 41 cases of appendectomy, 21 cases of partial cecectomy, 48 cases of right hemicolectomy, and 5 cases of combined organ resection due to appendiceal tumor infiltration or dissemination. Eighteen cases were diagnosed with pseudomyxoma peritonei (PMP) during operation. A total of 98 patients were enrolled for follow-up. The median follow-up time was 58 (5-172) months. The 5-year disease-free survival (DFS) rate was 84.5% and 5-year overall survival (OS) was 88.2%. Multivariate analysis revealed that high-grade malignancy tumors (HR=25.881, 95% CI: 2.827-236.935, P=0.004) and PMP formation (HR=42.166, 95% CI: 3.470-512.439,P=0.003) were independent risk factors for prognosis. Patients undergoing right hemicolectomy presented longer operation time, more blood loss and higher morbidity of complication as compared to those undergoing appendectomy and partial cecectomy (all P<0.05), while no significant differences in 5-year DFS (P=0.627) and 5-year OS (P=0.718) were found. Conclusions: Primary appendiceal neoplasms usually have no typical features, accompanied with low preoperative diagnosis rate. The common pathological types are LAMN, mucinous adenocarcinoma and aNEN. Appendectomy or partial cecectomy for LAMN may achieve satisfactory prognosis. High-grade malignancy tumors and PMP formation are independent risk factors for prognosis.

Clinicopathologic Features of Low-grade Appendiceal Mucinous Neoplasm: A Single-institution Experience of 117 Cases.

Low-grade appendiceal mucinous neoplasm (LAMN) is an enigmatic tumor that lacks the capacity for classic invasion but can dissect through the appendiceal wall, causing pseudomyxoma peritonei (PMP). Most large studies of the histologic spectrum of LAMN and its rate of associated PMP include cases submitted from outside institutions, potentially skewing their findings. We identified 117 cases of LAMN at our institution. Hematoxylin and eosin-stained slides from each were reviewed, and clinical and pathologic parameters were noted. The patients were 76 females and 41 males, with a mean age of 60 years. Presenting symptoms were available for 113 patients; the majority (56%) were symptomatic, typically with abdominal pain. Ninety-one tumors (78%) were grossly dilated, and the entire appendix was submitted in 88 (75%) cases. Median lesion size was 5.5 cm. Ninety-two cases (79%) demonstrated epithelial denudation; these were often markedly dilated and contained intraluminal or mural microcalcifications. Thirty-two (27%) had a mucosal Schwann cell proliferation. On the basis of the American Joint Committee on Staging eighth edition cancer staging manual, of 117 cases, 66% were staged as pTis, 9% as pT3, 24% as pT4a, and 2% as pT4b. Ten cases (9%) were associated with histopathologic evidence of disseminated PMP. Only 1 patient died of disease, while 3 were alive with disease at last follow-up. Previous LAMN studies have utilized both departmental and extradepartmental material; our single-institution review demonstrated lower rates of PMP than some prior studies. Some LAMNs may be markedly dilated with extensive denudation, making the diagnosis difficult to confirm microscopically and ultimately requiring submission of the entire appendix for histologic evaluation.

Low Grade Appendiceal Mucinous Neoplasm: A Report of Three Cases

Low-grade appendiceal mucinous neoplasm (LAMN) is an uncommon malignancy with varied clinical features. The most alarming complication of this neoplasm is seeding of mucin into the adjacent peritoneum leading to pseudomyxoma peritonei (PMP). We report three cases of LAMN. Two cases were seen post appendicectomy in 23-year old and 36-year old females. The third case was seen in 53-year-old male post Whipple procedure and hemicolectomy. LAMNs are often diagnosed incidentally, as clinical presentation is barely specific and resembles acute appendicitis. Hence it is imperative to examine all appendicectomy specimens not to miss cases of appendiceal mucinous neoplasm which can have implications on the further management of the patient.

Low Grade Appendiceal Mucinous Neoplasm: A Report of Three Cases

Low-grade appendiceal mucinous neoplasm (LAMN) is an uncommon malignancy with varied clinical features. The most alarming complication of this neoplasm is seeding of mucin into the adjacent peritoneum leading to pseudomyxoma peritonei (PMP). We report three cases of LAMN. Two cases were seen post appendicectomy in 23-year old and 36-year old females. The third case was seen in 53-year-old male post Whipple procedure and hemicolectomy. LAMNs are often diagnosed incidentally, as clinical presentation is barely specific and resembles acute appendicitis. Hence it is imperative to examine all appendicectomy specimens not to miss cases of appendiceal mucinous neoplasm which can have implications on the further management of the patient.

SATB2 is a supportive marker for the differentiation of a primary mucinous tumor of the ovary and an ovarian metastasis of a low-grade appendiceal mucinous neoplasm (LAMN): A series of seven cases

The differentiation between a primary mucinous ovarian neoplasm and an extra-ovarian metastasis in the ovary is often challenging in the histopathologic practice. Among various ovarian metastases from the gastro-intestinal tract the low-grade appendiceal mucinous neoplasm (LAMN) is an important differential diagnosis to consider particularly in case of pseudomyxoma peritonei. A newly recognized marker in the routine diagnostic of a mucinous neoplasm in the ovary is SATB2 (Special AT-rich sequence-binding protein 2). The expression of SATB2 is, within cells of epithelial lineages, mainly restricted to the lower gastro-intestinal tract, indicating colorectal or appendiceal cancer origin. We report seven cases of LAMN, which clinically became apparent due to ovarian metastases in context of pseudomyxoma peritonei or at least small foci of peritoneal tumor spread. An immunohistochemical marker-panel including SATB2, CDX2, CK20, CK7, PAX8, ER and PR revealed a strong expression of SATB2 in all seven cases. On the contrary SATB2-negativity could be demonstrated in the 40 cases of mucinous borderline tumors and primary mucinous carcinomas of the ovary. The histopathologic tentative diagnosis of an ovarian metastasis of LAMN could be confirmed in the findings of the Appendix in six of seven cases. This report supports SATB2 as an additional diagnostic marker for the diagnosis of an ovarian manifestation of LAMN.