Clin J Gastroenterol (2012) 5:220–224 DOI 10.1007/s12328-012-0302-9
CASE REPORT
Rupture of appendiceal mucocele due to endometriosis: report of a case Yasuyuki Miyakura • Hidetoshi Kumano • Hisanaga Horie • Alan T. Lefor • Yoshikazu Yasuda Takehiko Yamaguchi • Hiroshi Azuma
•
Received: 3 January 2012 / Accepted: 9 April 2012 / Published online: 28 April 2012 Ó Springer 2012
Abstract We report a rare case of a mucocele of the appendix due to endometriosis which accidentally ruptured prior to surgery. A 56-year-old woman was referred to our institution for further evaluation of a cecal tumor. Colonoscopy showed a submucosal tumor at the appendiceal orifice in the cecum. Computed tomography and magnetic resonance imaging showed a well-circumscribed mass measuring 4 cm in diameter in the right lower quadrant. A preoperative diagnosis of a simple mucocele of the appendix was established. At laparotomy, a mucocele was identified in the right side of the abdomen; however, part of the mucocele had ruptured and yellow mucin was seen around the cecum. An ileocecal resection was performed. Histopathological examination was consistent with a mucocele of the appendix due to endometriosis. Cytology specimens from the yellow mucin showed few proliferating epithelial cells with a mild degree of cytological and architectural atypia. Mechanical pressure due to excess anteflexion during administration of epidural anesthesia may have contributed to the rupture of the mucocele. It is important to handle a mucocele of the appendix with great
Y. Miyakura (&) H. Kumano H. Horie A. T. Lefor Y. Yasuda Departments of Surgery, Jichi Medical University, 3311-1 Yakushiji, Shimotsuke, Tochigi 329-0498, Japan e-mail: [email protected] Y. Miyakura H. Kumano H. Horie A. T. Lefor T. Yamaguchi Department of Pathology, Jichi Medical University, 3311-1 Yakushiji, Shimotsuke, Tochigi 329-0498, Japan Y. Miyakura H. Kumano H. Horie A. T. Lefor H. Azuma Utsunomiya Coloproctology Clinic, 1-1-7 Daikan-chou, Utsunomiya, Tochigi 320-0867, Japan
123
care to avoid rupture at the time of operation, including during the administration of epidural anesthesia. Keywords Rupture
Endometriosis Appendix Mucocele
Introduction Mucocoele of the appendix denotes an obstructive dilatation of the appendiceal lumen due to abnormal accumulation of mucus, which may be associated with epithelial regions such as mucosal hyperplasia and epithelial neoplasia [1, 2]. Some mucoceles of the appendix are caused by mucus distention secondary to obstruction of the appendix, a so-called simple mucocele, due to fecaliths, postinflammatory scarring or, rarely, endometriosis [3]. It is difficult to diagnose these pathological conditions preoperatively. Rupture of a mucocele leads to the dissemination of mucin and the mucin secreting malignant cells into the peritoneal cavity causing pseudomyxoma peritonei. It is important to handle a mucocele of the appendix with great care and avoid rupture at the time of operation. We report a rare case of a mucocele of the appendix caused by endometriosis, which accidentally ruptured prior to surgery. The exaggerated anteflexion position during administration of epidural anesthesia may be a possible cause of rupture of the mucocele.
Case report A 56-year-old woman presented to a local hospital for evaluation of a positive fecal occult blood test. Colonoscopy revealed a submucosal tumor at the cecum and
Clin J Gastroenterol (2012) 5:220–224
computed tomography (CT) showed a low-density tumor measuring about 4 cm in diameter in the right side of the abdomen. An appendiceal tumor was suspected and the patient was referred to our institution for further evaluation. There were no gastrointestinal symptoms. Her menstrual history was normal. She had a past history of surgery for bilateral ovarian tumors. Physical examination revealed a healthy woman in no acute distress with normal vital signs. Her cardiovascular and pulmonary findings were within normal limits. Abdominal examination revealed normal active bowel sounds in all four quadrants. Her abdomen had a scar from previous surgery and was soft, without any evidence of tenderness or peritoneal signs. Laboratory studies were normal. Colonoscopy showed a submucosal lesion about 4 cm in diameter in the cecum (Fig. 1a). The surface of the lesion was smooth and covered with normal mucosa. The appendiceal orifice was seen, but there was no mucus discharge (Fig. 1b). The shape of the submucosal tumor was altered by pressure from the biopsy forceps,
221
representing a positive ‘cushion-sign’ (Fig. 1c). Contrastenhanced CT of the abdomen showed a well-circumscribed low-density mass measuring 4 cm in diameter in the right lower quadrant (Fig. 2a, b). Magnetic resonance imaging (MRI) showed a well-circumscribed mass with low signal intensity on T1-weighted images and high signal intensity on T2-weighted images (Fig. 2c, d). A preoperative diagnosis of a simple mucocele of the appendix was made. Epidural anesthesia was administered in the left lateral decubitus position, to support anesthesia and for postoperative pain control, prior to the induction of general anesthesia. As catheter insertion was difficult through the epidural needle, the patient was re-positioned in an exaggerated anteflexed position. The knees were flexed and drawn up to the abdomen and the head was brought down toward the knees as much as possible. Catheter insertion was then retried, and was successful. At laparotomy, a mucocele was noted on the right side of the abdomen. Part of the mucocele was already ruptured
Fig. 1 Colonoscopy findings. Colonoscopy showed a submucosal tumor (a) with the appendiceal orifice (b), about 4 cm in diameter in the cecum. The shape of the submucosal tumor was altered by pressure from the biopsy forceps, representing a positive ‘cushion-sign’ (c)
123
222
Clin J Gastroenterol (2012) 5:220–224
Fig. 2 Contrast-enhanced CT scan and MRI findings. On axial (a) and coronal images (b) of the contrast-enhanced CT scan, a wellcircumscribed low-density mass measuring 4 cm in diameter (white arrow) in the right lower quadrant was identified. A mucocele
appeared as a cystic mass of low to intermediate signal intensity on T1-weighted sequences (c) and high signal intensity on T2-weighted sequences (d)
and yellow mucin was seen around the cecum (Fig. 3a). Features of endometriosis were not noted in the pelvis, involving the uterus. There were no other abnormalities in the peritoneal cavity. An ileocecal resection was performed and the mucin was removed from the abdominal cavity. The mucocele of the appendix measured 4 9 2 cm and contained mucus (Fig. 3b). Histopathological examination of the resected specimen showed that it was a simple-type mucocele and the wall consisted of a layer of mucin-producing columnar epithelium (Fig. 3c). Immunostaining studies showed that cytokeratin 7 and estrogen receptors were positive and cytokeratin 20 and progesterone receptors were negative in the ductal cells within the muscularis propria adjacent to the mucocele wall, suggesting that the mucocele of the appendix was due to endometriosis (Fig. 3d, e). Cytology specimens from the yellow mucin around the cecum showed very few proliferating epithelial cells with a mild degree of cytological and architectural atypia. The postoperative course was uneventful and the
patient is currently well with no evidence of recurrence 3 years after surgery.
123
Discussion Endometriosis of the appendix is a rare lesion and often discovered only as an incidental finding on histological examination following appendectomy. It is reported in 0.8 % of cases of appendectomy [4]. Some cases may mimic acute appendicitis while others present with cyclical right lower abdominal pain. A mucocele of the appendix is also an infrequent event, representing just 0.2–0.3 % of all appendix specimens, which may be associated with hyperplastic or neoplastic mucosal proliferation [1, 2]. Mucocele of the appendix caused by endometriosis is extremely rare. There have only been seven previously reported cases in the English literature [3, 5–9]. We describe here a rare case of mucocele of the appendix
Clin J Gastroenterol (2012) 5:220–224
223
Fig. 3 Findings included mucin at the time of laparotomy (a), the surgically resected specimen (b) and histopathological examination of the resected specimen (c–e). Yellow mucin was seen around the cecum (a). The mucocele of the appendix measured 4 9 2 cm (b) and contained mucus. Red circle shows the lumen of the mucocele. The white arrow shows the perforation site. The yellow arrow shows the
appendiceal orifice. The ductal cells of endometriosis are located in the yellow area. The mucocele wall consisted of a layer of mucinproducing columnar epithelium (c). Immunostaining showed that estrogen receptors were positive in the ductal cells within the muscular propria adjacent to the mucocele wall (e), suggesting a mucocele of the appendix due to endometriosis
caused by endometriosis, which accidentally ruptured prior to operation. This is the second reported case of a ruptured mucocele due to endometriosis. The key finding in mucocele of the appendix on colonoscopy is a submucosal tumor at the appendiceal orifice [10], which was seen in the present case. CT and MRI studies are helpful in determining the site of the tumor
origin. On MRI, a mucocele appears as a cystic mass at the expected location of the appendix with low to intermediate signal intensity on T1-weighted sequences and high signal intensity on T2-weighted sequences, which is attributed to the high protein content of the mucocele [11]. The MRI findings in the present case are compatible with these characteristics. A clinical diagnosis of a simple mucocele
123
224
of unknown etiology of the appendix was established for this patient prior to surgery. Laparotomy was performed to avoid rupture of the mucocele of the appendix because a ruptured mucocele may lead to dissemination of the mucin causing pseudomyxoma peritonei. The cause of rupture of an appendiceal mucocele is most likely either spontaneous or iatrogenic. Spontaneous rupture reportedly occurs in cases due to severe luminal distension [12]. Iatrogenic rupture is usually caused by inadvertent rupture of the lesion during operation. In this patient, the mucocele was already ruptured at laparotomy and yellow mucin was seen around the cecum. There was no episode of abdominal trauma causing rupture of the mucocele in this patient preoperatively. Positioning during administration of epidural anesthesia was suspected as a possible cause of accidental rupture of the appendiceal mucocele. An exaggerated anteflexion position was needed for epidural catheter insertion due to difficulty in placing the catheter in the usual manner. Furthermore, the patient described a feeling associated with rupture of the mucocele during placement of the epidural catheter. There are no similar previous reports mentioning the rupture of appendiceal mucocele possibly being caused by epidural anesthesia and general anesthesia. Although spontaneous rupture cannot be ruled out, positioning during administration of epidural anesthesia is considered a possible cause of rupture of the mucocele. Mechanical pressure due to excess flexion during epidural anesthesia increases the risk of tissue damage to the wall of the mucocele. Pseudomyxoma peritonei is the macroscopic presence of mucinous material in the peritoneal cavity. The amount of proliferating epithelium associated with the mucus and the degree of cytological and architectural atypia are important for assessing the prognosis [13]. In the present case, cytology specimens from the mucin in the peritoneal cavity showed very few proliferating epithelial cells with a mild degree of cytological and architectural atypia. Both this case and the previously reported case of a ruptured mucocele due to endometriosis developed no recurrence with pseudomyxoma peritonei after surgery. Simple or retention mucoceles due to obstruction of the appendiceal outflow by endometriosis may have few atypical cells, suggesting a low risk of developing pseudomyxoma peritonei. In summary, we report a rare case of mucocele of the appendix caused by endometriosis, which accidentally
123
Clin J Gastroenterol (2012) 5:220–224
ruptured prior to surgery. Mechanical pressure due to excess flexion during administration of epidural anesthesia may have led to rupture of the mucocele. It is important to handle a mucocele of the appendix with great care and avoid rupture at the time of operation, even during the administration of epidural anesthesia. Conflict of interest All authors have no conflict of interest and also have no financial relationship with the organization that sponsored this research.
References 1. Woodruff R, McDonald J. Benign and malignant cystic tumors of the appendix. Surg Gynecol Obstet. 1940;71:751–5. 2. Dhage-Ivatury S, Sugarbaker PH. Update on the surgical approach to mucocele of the appendix. J Am Coll Surg. 2006;202:680–4. 3. Hapke MR, Bigelow B. Mucocele of the appendix secondary to obstruction by endometriosis. Hum Pathol. 1977;8:585–9. 4. Uohara JK, Kobara TY. Endometriosis of the appendix. Am J Obstet Gynecol. 1975;121:423–6. 5. Driman DK, Melega DE, Vilos GA, Plewes EA. Mucocele of the appendix secondary to endometriosis: report of two cases, one with localized pseudomyxoma peritonei. Am J Clin Pathol. 2000;113:860–4. 6. Kimura H, Konishi K, Yabushita K, Maeda K, Tsuji M, Miwa A. Intussusception of a mucocele of the appendix secondary to an obstruction by endometriosis. Surg Today. 1999;29:629–32. 7. Nopajaroonsri C, Mreyoud N. Retention mucocele of appendix due to endometriosis. South Med J. 1994;87:833–5. 8. O’Sullivan MJ, Kumar U, Kiely EA. Ureteric obstruction with mucocoele of the appendix due to endometriosis. BJOG. 2001;108:124–5. 9. Abrao MS, Podgaec S, Carvalho FM, Gonc¸alves MO, Dias JA Jr, Averbach M. Bowel endometriosis and mucocele of the appendix. J Minim Invasive Gynecol. 2005;12:299–300. 10. Hamiliton D, Stormont J. The volcano sign of appendiceal mucocele. Gastrointest Endosc. 1989;35:453–5. 11. Koga H, Aoyagi K, Honda H, Fujishima M. Appendiceal mucocele: sonographic and MR imaging findings. Am J Roentgenol. 1995;165:1552. 12. Rampone B, Roviello F, Marrelli D, Pinto E. Giant appendiceal mucocele: report of a case and brief review. World J Gastroenterol. 2005;11:4761–3. 13. Ronnett BM, Zahn CM, Kurman RJ, Kass ME, Sugarbaker PH, Shmookler BM. Disseminated peritoneal adenomucinosis and peritoneal mucinous carcinomatosis. A clinicopathologic analysis of 109 cases with emphasis on distinguishing pathologic features, site of origin, prognosis, and relationship to ‘‘pseudomyxoma peritonei’’. Am J Surg Pathol. 1995;19:1390–408.
CASE REPORT
Rupture of appendiceal mucocele due to endometriosis: report of a case Yasuyuki Miyakura • Hidetoshi Kumano • Hisanaga Horie • Alan T. Lefor • Yoshikazu Yasuda Takehiko Yamaguchi • Hiroshi Azuma
•
Received: 3 January 2012 / Accepted: 9 April 2012 / Published online: 28 April 2012 Ó Springer 2012
Abstract We report a rare case of a mucocele of the appendix due to endometriosis which accidentally ruptured prior to surgery. A 56-year-old woman was referred to our institution for further evaluation of a cecal tumor. Colonoscopy showed a submucosal tumor at the appendiceal orifice in the cecum. Computed tomography and magnetic resonance imaging showed a well-circumscribed mass measuring 4 cm in diameter in the right lower quadrant. A preoperative diagnosis of a simple mucocele of the appendix was established. At laparotomy, a mucocele was identified in the right side of the abdomen; however, part of the mucocele had ruptured and yellow mucin was seen around the cecum. An ileocecal resection was performed. Histopathological examination was consistent with a mucocele of the appendix due to endometriosis. Cytology specimens from the yellow mucin showed few proliferating epithelial cells with a mild degree of cytological and architectural atypia. Mechanical pressure due to excess anteflexion during administration of epidural anesthesia may have contributed to the rupture of the mucocele. It is important to handle a mucocele of the appendix with great
Y. Miyakura (&) H. Kumano H. Horie A. T. Lefor Y. Yasuda Departments of Surgery, Jichi Medical University, 3311-1 Yakushiji, Shimotsuke, Tochigi 329-0498, Japan e-mail: [email protected] Y. Miyakura H. Kumano H. Horie A. T. Lefor T. Yamaguchi Department of Pathology, Jichi Medical University, 3311-1 Yakushiji, Shimotsuke, Tochigi 329-0498, Japan Y. Miyakura H. Kumano H. Horie A. T. Lefor H. Azuma Utsunomiya Coloproctology Clinic, 1-1-7 Daikan-chou, Utsunomiya, Tochigi 320-0867, Japan
123
care to avoid rupture at the time of operation, including during the administration of epidural anesthesia. Keywords Rupture
Endometriosis Appendix Mucocele
Introduction Mucocoele of the appendix denotes an obstructive dilatation of the appendiceal lumen due to abnormal accumulation of mucus, which may be associated with epithelial regions such as mucosal hyperplasia and epithelial neoplasia [1, 2]. Some mucoceles of the appendix are caused by mucus distention secondary to obstruction of the appendix, a so-called simple mucocele, due to fecaliths, postinflammatory scarring or, rarely, endometriosis [3]. It is difficult to diagnose these pathological conditions preoperatively. Rupture of a mucocele leads to the dissemination of mucin and the mucin secreting malignant cells into the peritoneal cavity causing pseudomyxoma peritonei. It is important to handle a mucocele of the appendix with great care and avoid rupture at the time of operation. We report a rare case of a mucocele of the appendix caused by endometriosis, which accidentally ruptured prior to surgery. The exaggerated anteflexion position during administration of epidural anesthesia may be a possible cause of rupture of the mucocele.
Case report A 56-year-old woman presented to a local hospital for evaluation of a positive fecal occult blood test. Colonoscopy revealed a submucosal tumor at the cecum and
Clin J Gastroenterol (2012) 5:220–224
computed tomography (CT) showed a low-density tumor measuring about 4 cm in diameter in the right side of the abdomen. An appendiceal tumor was suspected and the patient was referred to our institution for further evaluation. There were no gastrointestinal symptoms. Her menstrual history was normal. She had a past history of surgery for bilateral ovarian tumors. Physical examination revealed a healthy woman in no acute distress with normal vital signs. Her cardiovascular and pulmonary findings were within normal limits. Abdominal examination revealed normal active bowel sounds in all four quadrants. Her abdomen had a scar from previous surgery and was soft, without any evidence of tenderness or peritoneal signs. Laboratory studies were normal. Colonoscopy showed a submucosal lesion about 4 cm in diameter in the cecum (Fig. 1a). The surface of the lesion was smooth and covered with normal mucosa. The appendiceal orifice was seen, but there was no mucus discharge (Fig. 1b). The shape of the submucosal tumor was altered by pressure from the biopsy forceps,
221
representing a positive ‘cushion-sign’ (Fig. 1c). Contrastenhanced CT of the abdomen showed a well-circumscribed low-density mass measuring 4 cm in diameter in the right lower quadrant (Fig. 2a, b). Magnetic resonance imaging (MRI) showed a well-circumscribed mass with low signal intensity on T1-weighted images and high signal intensity on T2-weighted images (Fig. 2c, d). A preoperative diagnosis of a simple mucocele of the appendix was made. Epidural anesthesia was administered in the left lateral decubitus position, to support anesthesia and for postoperative pain control, prior to the induction of general anesthesia. As catheter insertion was difficult through the epidural needle, the patient was re-positioned in an exaggerated anteflexed position. The knees were flexed and drawn up to the abdomen and the head was brought down toward the knees as much as possible. Catheter insertion was then retried, and was successful. At laparotomy, a mucocele was noted on the right side of the abdomen. Part of the mucocele was already ruptured
Fig. 1 Colonoscopy findings. Colonoscopy showed a submucosal tumor (a) with the appendiceal orifice (b), about 4 cm in diameter in the cecum. The shape of the submucosal tumor was altered by pressure from the biopsy forceps, representing a positive ‘cushion-sign’ (c)
123
222
Clin J Gastroenterol (2012) 5:220–224
Fig. 2 Contrast-enhanced CT scan and MRI findings. On axial (a) and coronal images (b) of the contrast-enhanced CT scan, a wellcircumscribed low-density mass measuring 4 cm in diameter (white arrow) in the right lower quadrant was identified. A mucocele
appeared as a cystic mass of low to intermediate signal intensity on T1-weighted sequences (c) and high signal intensity on T2-weighted sequences (d)
and yellow mucin was seen around the cecum (Fig. 3a). Features of endometriosis were not noted in the pelvis, involving the uterus. There were no other abnormalities in the peritoneal cavity. An ileocecal resection was performed and the mucin was removed from the abdominal cavity. The mucocele of the appendix measured 4 9 2 cm and contained mucus (Fig. 3b). Histopathological examination of the resected specimen showed that it was a simple-type mucocele and the wall consisted of a layer of mucin-producing columnar epithelium (Fig. 3c). Immunostaining studies showed that cytokeratin 7 and estrogen receptors were positive and cytokeratin 20 and progesterone receptors were negative in the ductal cells within the muscularis propria adjacent to the mucocele wall, suggesting that the mucocele of the appendix was due to endometriosis (Fig. 3d, e). Cytology specimens from the yellow mucin around the cecum showed very few proliferating epithelial cells with a mild degree of cytological and architectural atypia. The postoperative course was uneventful and the
patient is currently well with no evidence of recurrence 3 years after surgery.
123
Discussion Endometriosis of the appendix is a rare lesion and often discovered only as an incidental finding on histological examination following appendectomy. It is reported in 0.8 % of cases of appendectomy [4]. Some cases may mimic acute appendicitis while others present with cyclical right lower abdominal pain. A mucocele of the appendix is also an infrequent event, representing just 0.2–0.3 % of all appendix specimens, which may be associated with hyperplastic or neoplastic mucosal proliferation [1, 2]. Mucocele of the appendix caused by endometriosis is extremely rare. There have only been seven previously reported cases in the English literature [3, 5–9]. We describe here a rare case of mucocele of the appendix
Clin J Gastroenterol (2012) 5:220–224
223
Fig. 3 Findings included mucin at the time of laparotomy (a), the surgically resected specimen (b) and histopathological examination of the resected specimen (c–e). Yellow mucin was seen around the cecum (a). The mucocele of the appendix measured 4 9 2 cm (b) and contained mucus. Red circle shows the lumen of the mucocele. The white arrow shows the perforation site. The yellow arrow shows the
appendiceal orifice. The ductal cells of endometriosis are located in the yellow area. The mucocele wall consisted of a layer of mucinproducing columnar epithelium (c). Immunostaining showed that estrogen receptors were positive in the ductal cells within the muscular propria adjacent to the mucocele wall (e), suggesting a mucocele of the appendix due to endometriosis
caused by endometriosis, which accidentally ruptured prior to operation. This is the second reported case of a ruptured mucocele due to endometriosis. The key finding in mucocele of the appendix on colonoscopy is a submucosal tumor at the appendiceal orifice [10], which was seen in the present case. CT and MRI studies are helpful in determining the site of the tumor
origin. On MRI, a mucocele appears as a cystic mass at the expected location of the appendix with low to intermediate signal intensity on T1-weighted sequences and high signal intensity on T2-weighted sequences, which is attributed to the high protein content of the mucocele [11]. The MRI findings in the present case are compatible with these characteristics. A clinical diagnosis of a simple mucocele
123
224
of unknown etiology of the appendix was established for this patient prior to surgery. Laparotomy was performed to avoid rupture of the mucocele of the appendix because a ruptured mucocele may lead to dissemination of the mucin causing pseudomyxoma peritonei. The cause of rupture of an appendiceal mucocele is most likely either spontaneous or iatrogenic. Spontaneous rupture reportedly occurs in cases due to severe luminal distension [12]. Iatrogenic rupture is usually caused by inadvertent rupture of the lesion during operation. In this patient, the mucocele was already ruptured at laparotomy and yellow mucin was seen around the cecum. There was no episode of abdominal trauma causing rupture of the mucocele in this patient preoperatively. Positioning during administration of epidural anesthesia was suspected as a possible cause of accidental rupture of the appendiceal mucocele. An exaggerated anteflexion position was needed for epidural catheter insertion due to difficulty in placing the catheter in the usual manner. Furthermore, the patient described a feeling associated with rupture of the mucocele during placement of the epidural catheter. There are no similar previous reports mentioning the rupture of appendiceal mucocele possibly being caused by epidural anesthesia and general anesthesia. Although spontaneous rupture cannot be ruled out, positioning during administration of epidural anesthesia is considered a possible cause of rupture of the mucocele. Mechanical pressure due to excess flexion during epidural anesthesia increases the risk of tissue damage to the wall of the mucocele. Pseudomyxoma peritonei is the macroscopic presence of mucinous material in the peritoneal cavity. The amount of proliferating epithelium associated with the mucus and the degree of cytological and architectural atypia are important for assessing the prognosis [13]. In the present case, cytology specimens from the mucin in the peritoneal cavity showed very few proliferating epithelial cells with a mild degree of cytological and architectural atypia. Both this case and the previously reported case of a ruptured mucocele due to endometriosis developed no recurrence with pseudomyxoma peritonei after surgery. Simple or retention mucoceles due to obstruction of the appendiceal outflow by endometriosis may have few atypical cells, suggesting a low risk of developing pseudomyxoma peritonei. In summary, we report a rare case of mucocele of the appendix caused by endometriosis, which accidentally
123
Clin J Gastroenterol (2012) 5:220–224
ruptured prior to surgery. Mechanical pressure due to excess flexion during administration of epidural anesthesia may have led to rupture of the mucocele. It is important to handle a mucocele of the appendix with great care and avoid rupture at the time of operation, even during the administration of epidural anesthesia. Conflict of interest All authors have no conflict of interest and also have no financial relationship with the organization that sponsored this research.
References 1. Woodruff R, McDonald J. Benign and malignant cystic tumors of the appendix. Surg Gynecol Obstet. 1940;71:751–5. 2. Dhage-Ivatury S, Sugarbaker PH. Update on the surgical approach to mucocele of the appendix. J Am Coll Surg. 2006;202:680–4. 3. Hapke MR, Bigelow B. Mucocele of the appendix secondary to obstruction by endometriosis. Hum Pathol. 1977;8:585–9. 4. Uohara JK, Kobara TY. Endometriosis of the appendix. Am J Obstet Gynecol. 1975;121:423–6. 5. Driman DK, Melega DE, Vilos GA, Plewes EA. Mucocele of the appendix secondary to endometriosis: report of two cases, one with localized pseudomyxoma peritonei. Am J Clin Pathol. 2000;113:860–4. 6. Kimura H, Konishi K, Yabushita K, Maeda K, Tsuji M, Miwa A. Intussusception of a mucocele of the appendix secondary to an obstruction by endometriosis. Surg Today. 1999;29:629–32. 7. Nopajaroonsri C, Mreyoud N. Retention mucocele of appendix due to endometriosis. South Med J. 1994;87:833–5. 8. O’Sullivan MJ, Kumar U, Kiely EA. Ureteric obstruction with mucocoele of the appendix due to endometriosis. BJOG. 2001;108:124–5. 9. Abrao MS, Podgaec S, Carvalho FM, Gonc¸alves MO, Dias JA Jr, Averbach M. Bowel endometriosis and mucocele of the appendix. J Minim Invasive Gynecol. 2005;12:299–300. 10. Hamiliton D, Stormont J. The volcano sign of appendiceal mucocele. Gastrointest Endosc. 1989;35:453–5. 11. Koga H, Aoyagi K, Honda H, Fujishima M. Appendiceal mucocele: sonographic and MR imaging findings. Am J Roentgenol. 1995;165:1552. 12. Rampone B, Roviello F, Marrelli D, Pinto E. Giant appendiceal mucocele: report of a case and brief review. World J Gastroenterol. 2005;11:4761–3. 13. Ronnett BM, Zahn CM, Kurman RJ, Kass ME, Sugarbaker PH, Shmookler BM. Disseminated peritoneal adenomucinosis and peritoneal mucinous carcinomatosis. A clinicopathologic analysis of 109 cases with emphasis on distinguishing pathologic features, site of origin, prognosis, and relationship to ‘‘pseudomyxoma peritonei’’. Am J Surg Pathol. 1995;19:1390–408.
![[Appendiceal mucocele: report of a case observed in Lubumbashi].](/assets/img/hold.png)
