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\begin{document}

\title{Ruptured Giant Low-grade Mucocele of the Appendix and its Management: A
Case Report}



\author[1]{Hritvik Jain}%
\author[1]{Dheerain Gupta}%
\author[1]{Jyoti Jain}%
\author[1]{Mahendra Lodha}%
\author[1]{Binit Surekha}%
\author[2]{Prakriti Pokhrel}%
\affil[1]{All India Institute of Medical Sciences - Jodhpur}%
\affil[2]{Kathmandu Medical College and Teaching Hospital}%


\vspace{-1em}



  
  \date{May 26, 2024}


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\textbf{Title:} Ruptured Giant Low-grade Mucocele of the Appendix and
its Management: A Case Report

\textbf{Key Clinical Message} :

Preoperative prompt imaging is crucial for a definitive diagnosis of
appendiceal mucocele, and double-J stenting of the ipsilateral ureter in
a large retroperitoneal cyst is recommended for easy identification and
prevention of complications.

\textbf{Keywords} :

Appendix; appendiceal neoplasms; mucocele; pseudomyxoma peritonei;
neoplasms; laparotomy

\textbf{Introduction} :

Mucocele of the appendix is a well-described clinical condition of the
appendix. It is a rare condition with an incidence of about 0.2-0.7 \%
of all appendectomies (1). The pathophysiology behind the appendiceal
mucocele is an obstructive dilatation of the appendicular lumen by
excess intra-luminal mucous secretions. Due to the presence of very
vague presenting symptoms or even asymptomatic presentation, it is often
diagnosed at an advanced clinical stage, or even misdiagnosed as acute
appendicitis. It requires prompt imaging with preoperative planning and
adequate surgical treatment, to avoid the rupture and spillage of the
cystic content and to prevent the development of pseudomyxoma peritonei.

\textbf{Case Presentation} :

A 60-year-old hypertensive male came to the general surgery outpatient
department with complaints of pain and distension in the abdomen for
three years which was insidious in onset and progressive in nature. On
examination, the abdomen was soft, non-tender, and distended with a
vague lump felt in the right half of the abdomen (Fig. 1). There were no
complaints of fever, weight loss, appetite loss, constipation, or
vomiting. Laboratory investigations showed leucocytosis (13.20 x
10\textsuperscript{3} /ul) with neutrophilia (9.09 x
10\textsuperscript{3} /ul), and carcinoembryonic antigen (CEA) levels
were elevated, 117.8 ng/ml.

Abdominal ultrasonography showed a large intra-abdominal lobulated
hypoechoic, likely cystic mass with internal echogenic areas on the
right side. Abdominal contrast-enhanced computed tomography showed a
large well defined multilobulated lesion of 17x13x24 cm in the
retroperitoneum on the right side along with areas of whorled
calcification in the superior aspect of the lesion. This gigantic cyst
was pushing the retroperitoneal organs towards the left side (Fig. 2).

Because of the large size of the mass, a decision to perform an
exploratory laparotomy was made. A full-length midline incision was
given and the mass was excised in toto with accidental spillage of
content along with the part of the cecum (Fig. 3, 4). Intraoperatively,
a large retroperitoneal cystic mass of 15.5 x 12 x 20 centimetres was
found in connection with the body of the appendix. The cyst was
extending superiorly to the dome of the diaphragm, medially to the
lateral border of the inferior vena cava and inferiorly to the
pelvis.~Histopathology samples of the mass and cell cytology samples of
the spillage liquid were sent. Microscopic examination of the cyst wall
showed flattened to undulating columnar lining epithelium which was
getting morphed into papillary infoldings, exhibiting mild nuclear
pleomorphism, round to oval coarsely chromatic nuclei, inconspicuous
nucleoli and abundant mucinous cytoplasm. The underlying lamina propria
showed moderate chronic inflammatory infiltrate and desmoplasia.
Histopathological diagnosis of ``Low grade appendiceal mucinous
neoplasm, pT4a'' was made. The appendix base and part of the cecum were
not involved in the tumour. The patient was discharged on a
postoperative day-7 and has been followed up in the outpatient
department with no reported complications for 6 months.

\textbf{Discussion} :

Mucocele was initially described by Rokitansky in 1842 (2). Most often,
benign or malignant epithelial proliferation results in an obstructive
dilatation of the appendix. Less frequently, inflammation or obstruction
by a fecalith is the cause of mucocele formation (3). Some studies state
a higher prevalence in females (1), while others confirm a higher
prevalence in males (4). At our tertiary care referral centre, we have
found that males above 50 years of age are more commonly affected by
appendiceal mucocele.

The clinical presentation of appendiceal mucocele is vague or sometimes
asymptomatic. Due to this, patients often present late to the hospital.
Usually delayed presentations of appendiceal mucocele are large
abdominal lump, abdominal distension, acute appendicitis or acute
abdomen or pseudomyxoma peritonei. Without proper in-time treatment, the
whole abdomen may get involved due to perforation of the mucocele and
dissemination of the mucin-producing epithelium in the peritoneal
cavity, which may result in the development of pseudomyxoma peritonei.
In our scenario, the patient presented to us with a large abdominal lump
and abdominal distension. Ultrasound showed the classical onion skin
sign suggestive of appendiceal mucocele (5). A contrast-enhanced
computed tomography was performed for further characterization of the
cystic mass and surgical planning. A correct diagnosis before surgery is
of paramount importance for both planning the surgery and decreasing the
risk of severe intraoperative and postoperative complications. The
imaging techniques that can aid in the diagnosis of mucocele of the
appendix are ultrasonography, computed tomography and colonoscopy.

On computed tomography, a mucocele will typically manifest as a
homogenous hypoattenuating material that has Hounsfield values similar
to water filling the lumen of the appendix (3). A mucocele is highly
likely if there is curvilinear calcification in the appendix's wall (6).
An elevated appendiceal mucocele can be seen during a colonoscopy and is
called as ``volcano sign'' (7). A yellowish mucus discharge may be
visible from this orifice (8). Histopathology is usually the standard
investigation for establishing a definitive diagnosis of mucocele.
Because of the risk of seeding neoplastic cells along the needle track
or in the peritoneal cavity, which could produce pseudomyxoma peritonei,
fine needle aspiration of an appendiceal mucocele is avoided (9).

The treatment modality of choice for appendiceal mucocele is surgery.
The basic guiding principle behind the surgery for an appendiceal
mucocele is to retrieve the cyst intact without spillage, as a
perforated appendiceal mucocele carries a higher risk of development of
pseudomyxoma peritonei. The surgical method preferred for operating on
the mucocele of the appendix is open surgery because of the higher risk
of rupture of the mucocele laparoscopically (10). In open surgery, it is
possible to do a complete in-situ manual examination of the intestines
including palpation of the inflamed structure and also direct inspection
of the most probable spots of mucinous tumours in the abdomen.
Laparoscopic exploration does help in the confirmation of diagnosis. But
now, because of the availability of high-resolution computed tomography
with good diagnostic accuracy, a laparoscopic examination is seldom
required.

Our case showcases the importance of large size and location in the
retroperitoneum of the appendiceal mucocele. Preoperative double-J
stenting of the right ureter should be done in the retroperitoneal
appendiceal mucocele for easy identification of the right ureter.
Meticulous intraoperative handling and dissection are required to
prevent the rupture of the cyst and its complications. An appendectomy,
ileocecectomy or right hemicolectomy should be the only procedure
performed during the initial surgery for a ruptured appendiceal mucinous
lesion at non-specialized centres. Additionally, careful inspection of
the abdominal cavity with documentation and biopsy of any suspicious
peritoneal lesions should be done. To minimize tumour cell implantation,
the surgical and abdomen wounds should be cleaned thoroughly by
irrigation (11).

Depending on the final detected pathology, a patient with gross
peritoneal dissemination of mucin should thereafter be transferred to a
specialized centre. A consensus classification developed by the
Peritoneal Surface Oncology Group International has been instrumental in
clearing up the ambiguity around diagnostic terminology (12).

Our case was reported as ``T4a low-grade mucinous neoplasm'', which
should be managed with follow-up contrast-enhanced computed tomography
or diagnostic laparoscopy at 6 to 12 months to look for recurrence or
development of the tumour. Cytoreductive surgery/hyperthermic
intraperitoneal chemotherapy can then be offered if evidence of disease
is detected.

\textbf{Conclusion} :

Appendiceal mucocele, albeit a rare disease, should always be kept as a
differential diagnosis when the presenting symptoms are like acute
appendicitis. Clinicians should be aware that the underlying pathology
behind a mucocele of the appendix can range from a mere retention cyst
to malignant tumours. To correctly diagnose a mucocele pre-operatively,
contrast-enhanced computed tomography abdomen should be used
extensively. The importance of contrast-enhanced computed tomography and
other imaging modalities increases in large-size cysts. For larger cysts
located in the retroperitoneum, preoperative double-J stenting of the
right ureter is recommended for easy identification. Meticulous
dissection to prevent spillage and to avoid the development of
pseudomyxoma peritonei is a must.

\textbf{Author Contributions} :

\textbf{Hritvik Jain} : Conceptualization; writing -- original draft;
writing -- review \& editing. \textbf{Dheerain Gupta} :
Conceptualization; writing -- original draft, writing -- review \&
editing. \textbf{Jyoti Jain} : Writing -- original draft, writing --
review \& editing. \textbf{Mahendra Lodha} : Methodology; project
administration; supervision; writing -- review \& editing. \textbf{Binit
Sureka} : Writing -- original draft. \textbf{Prakriti Pokhrel} : Writing
-- original draft.

\textbf{References} :

(1). Singh MP.(2020) A general overview of mucocele of appendix.9(12),
5867-5871.

(2). B.B., S.K., Jasuja P.(2019) Appendiceal mucocele-A rare case
report.58, 21-25.

(3). Demetrashvili Z, Chkhaidze M, Khutsishvili K et al.(2012) Mucocele
of the Appendix: Case Report and Review of Literature.97(3), 266-269.

(4). Saad EA, Elsamani EY, AbdElrahim WE et al.(2018) Surgical treatment
of mucocele of the appendix.2018(6), rjy102.

(5). Caspi B, Cassif E, Auslender R et al.(2004) The onion skin sign: A
specific sonographic marker of appendiceal mucocele.23(1), 117-121.

(6). Tirumani SH, Fraser-Hill M, Auer R et al.(2013) Mucinous neoplasms
of the appendix: A current comprehensive clinicopathologic and imaging
review.13(1), 14-25.

(7). Mastoraki A, Sakorafas G, Vassiliu P et al.(2016) Mucocele of the
Appendix: Dilemmas in Differential Diagnosis and Therapeutic
Management.7(1), 86-90.

(8). Pickhardt PJ, Levy AD, Rohrmann CA et al.(2003) Primary neoplasms
of the appendix: Radiologic spectrum of disease with pathologic
correlation.23(3), 645-662.

(9). da Fonseca LM, Lacerda-Filho A, da Silva RG.(2010) Pseudomyxoma
peritonei syndrome 12 months after an intact resection of malignant
mucocele of the appendix: A case report.65(8), 817-818.

(10). Zuzarte JC, Liu YC, Cohen AM.(1996) Fine needle aspiration
cytology of appendiceal mucinous cystadenoma: A case report.40(2),
327-330.

(11). Barrios P, Losa F, Gonzalez-Moreno S et al.(2016) Recommendations
in the management of epithelial appendiceal neoplasms and peritoneal
dissemination from mucinous tumours (pseudomyxoma peritonei).18(5),
437-448.

(12). Govaerts K, Lurvink RJ, De Hingh IHJT et al.(2021) Appendiceal
tumours and pseudomyxoma peritonei: Literature review with PSOGI/EURACAN
clinical practice guidelines for diagnosis and treatment.47(1), 11-35.

\textbf{Figure Legends} :

Figure 1: Preoperative image of the patient's abdomen showing fullness
in left hypochondrium and left lumbar region.

Figure 2: CECT abdomen figure showing the axial (left side) and coronal
(right side) view. The white dashed arrow is showing the displaced colon
and the black dashed arrow is pointing towards the displaced right
kidney hence confirming it to be predominantly retroperitoneal in
location.

Figure 3: Intraoperative image showing an in-situ cystic mass occupying
the entire retroperitoneum.

Figure 4: Postoperative image showing an excised specimen with mucin.\selectlanguage{english}
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