Colon Cancer complicated by intrabdominal abscess and necrotizing fasciitis – a case report

Full article

https://doi.org/10.53453/ms.2025.11.3

Colon cancer complicated by intrabdominal abscess and

necrotizing fasciitis – a case report

Linas Prapiestis

, Saulius Švagždys

Faculty of Medicine, Lithuanian University of Health Sciences, Kaunas, Lithuania

Lithuanian University of Health Sciences Kaunas Clinics, Department of Surgery Kaunas, Lithuania

Abstract

Background. Colorectal cancer (CRC) is the second-leading cause of cancer-related death worldwide. While

complications like abscesses and fistulas are recognized in advanced disease, progression to necrotizing fasciitis

(NF) remains exceedingly rare and life-threatening. Early detection and multidisciplinary intervention are critical

for favorable outcomes.

Case presentation. We present a case of a 73-year-old woman initially evaluated for lower limb weakness, during

which radiological imaging incidentally revealed an infiltrative mass in the cecal region. Further workup showed

bowel obstruction and an intra-abdominal abscess extending into the iliopsoas muscle. Shortly after, she

developed necrotizing fasciitis of the right thigh. Emergency debridement was performed, followed by a right

hemicolectomy. Histology confirmed moderately differentiated adenocarcinoma of the ascending colon with local

invasion.

Conclusions. This case highlights the potential for CRC to present with severe, atypical infectious complications

such as necrotizing fasciitis. Rapid diagnosis, surgical intervention, and coordinated multidisciplinary care were

essential in achieving clinical stabilization and enabling oncologic treatment. Awareness of such rare presentations

is vital for timely management and improved prognosis in similar high-risk patients.

Keywords: colorectal cancer, necrotizing fasciitis, intra-abdominal abscess, fistula, ileopsoas infection, advanced

colon cancer.

Journal of Medical Sciences. 8 Nov, 2025 - Volume 13 | Issue 5. Electronic - ISSN: 2345-0592

Medical Sciences 2025 Vol. 13 (5), p. 26-33, https://doi.org/10.53453/ms.2025.11.3

1. Introduction

Colorectal cancer remains the second-leading

cause of cancer-related mortality worldwide, and

its incidence continues to rise, particularly

among aging populations (1). Multiple risk

factors contribute to the development of colon

cancer, including advanced age, a diet rich in red

or processed meats, low dietary fiber,

inflammatory bowel disease, family history, and

physical inactivity (2). Early detection through

screening modalities—such as colonoscopy,

fecal immunochemical testing, and colo-

noscopy—plays a critical role in reducing

mortality. When diagnosed early, patients

benefit from a multimodal treatment approach

involving surgery, chemotherapy, and in

selected cases, targeted therapies, all of which

improve survival and quality of life (3).

However, advanced-stage colon cancer presents

a different clinical challenge. As the tumor

progresses, it can lead to complex complications,

including bowel obstruction, gastrointestinal

bleeding, and perforation—each of which can

precipitate life-threatening conditions such as

peritonitis or sepsis. Fistula formation and

abscesses are also common, often signaling local

tissue destruction and invasion into adjacent

structures. These complications not only worsen

the prognosis but also necessitate urgent

multidisciplinary intervention (3). Fistulas occur

in approximately 20 % of colon cancer cases,

frequently coexisting with intra-abdominal

abscesses in up to 44 % of patients. These

pathological connections typically result from

direct tumor invasion into neighboring organs

such as the bladder, small intestine, or abdominal

wall. The pathophysiology involves initial

inflammatory adhesion followed by transmural

tumor infiltration and eventual breakdown of

structural barriers (4) . In rare cases, abscess

formation may extend into the psoas or iliopsoas

muscles, driven by bacterial translocation from a

perforated bowel segment. The fascial planes in

these muscles act as conduits for infection spread

into the retroperitoneum or thigh, complicating

the clinical course and increasing morbi-

dity (5,6).

Even more rarely, such infections may evolve

into necrotizing fasciitis, a fulminant soft tissue

infection characterized by rapid tissue destruc-

tion, systemic toxicity, and high mortality. This

devastating condition has been reported in

association with colorectal cancers—

particularly cecal or sigmoid tumors—when

tumor perforation introduces anaerobic enteric

organisms into adjacent soft tissues (7).

Necrotizing soft tissue infections (NSTIs),

including necrotizing fasciitis, remain rare but

deadly. Reported incidence ranges from 0.3 to 15

cases per 100,000 population (8). Mortality rates

are high—often between 32 % and 50 %—

primarily due to septic shock and multiorgan

failure. Risk factors include advanced age,

diabetes, immunosuppression, and delays in

initiating surgical debridement (9–11). The

cornerstone of NSTI management is prompt and

extensive surgical debridement of necrotic

tissue. Timely intervention improves outcomes

by controlling infection, preventing systemic

spread, and minimizing the need for limb

amputation. Debridement must include all

poorly perfused tissue, often requiring repeated

surgeries for adequate source control (12,13).

This report presents a rare and complex case of

necrotizing fasciitis secondary to advanced

colon cancer, initially complicated by intra-

abdominal abscess formation. The case

highlights diagnostic and therapeutic challenges,

underscores the importance of early recognition

and multidisciplinary management, and serves to

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enhance awareness of this potentially fatal

complication in oncologic practice.

2. Clinical case

A 73-year-old woman presented with a 3-week

history of worsening low back pain radiating into

the right leg, accompanied by numbness. She has

a long-standing history of lumbar spine issues

with periods of exacerbation and remission. Due

to the severity of current symptoms, lumbar

spine MRI was performed, which revealed no

significant spinal canal stenosis or disc

protrusions, but showed abnormal findings in the

right iliopsoas muscle, raising suspicion for a

possible inflammatory or infiltrative process and

prompting further pelvic imaging. Pelvic MRI

demonstrated edema in the perimuscular fat

surrounding the distal portion of the right

iliopsoas muscle, more pronounced in the iliacus

component, without clear fluid collections.

These findings were considered reactive, with

the center of the process located in the region of

the cecum. Notably, the cecal wall, distal ileum,

and particularly the ileocecal junction appeared

thickened, with surrounding edematous fat

containing small fluid pockets—features

suggestive of an inflammatory or possibly

neoplastic process. To further investigate, the

patient underwent esophagogastroduode-

noscopy, which showed no abnormalities, and

colonoscopy, which revealed an infiltrated,

edematous, erythematous, and stenotic mucosa

in the proximal ascending colon, raising

suspicion for either an inflammatory disease or

malignancy. Biopsies were obtained; however,

histological analysis showed preserved crypt and

glandular architecture with subepithelial edema

and mild mononuclear and granulocytic

infiltration, but no evidence of ulceration,

granulomas, dysplasia, or malignancy. Scattered

brown pigment granules, more prominent near

the muscularis mucosa, were noted, suggesting

possible melanosis. Overall, no neoplastic

changes were identified in the biopsy.

Following the colonoscopy, the patient began

experiencing cramping abdominal pain,

particularly localized to the right iliac region,

which persisted for several days. On physical

examination, the abdomen was soft but tender in

the right lower quadrant, where a palpable

infiltrate was noted. There were no signs of

peritoneal irritation or muscle guarding.

Laboratory tests revealed elevated inflammatory

markers with a C-reactive protein (CRP) of

72 mg/L, leukocytosis at 10.5 × 10⁹/L, and

neutrophilia (75%). Abdominal radiography

showed no free air under the diaphragm, but

small bowel loops were dilated up to 4.3 cm with

several air-fluid levels and significant intestinal

content, consistent with small bowel obstruction.

A contrast-enhanced abdominal CT scan (figure

1) demonstrated a 7.4 × 5.5 cm infiltrate with air

inclusions in the right lower quadrant, associated

with cecal wall edema (up to 1.1 cm thick) and

multiple fluid collections with air pockets along

the anterior abdominal wall (up to 5.0 × 2.0 cm)

and near the right iliacus muscle (up to 1.1 ×

6.0 cm), consistent with either a perforated cecal

or appendiceal process with abscess formation,

or necrotizing tumor-related changes.

Additionally, small bowel loops were dilated up

to 3.7 cm with focal mural thickening, indicating

small bowel obstruction with the transition point

in the cecal region. The patient was admitted to

the Department of Surgery at the Hospital of

Lithuanian University of Health Sciences

Kaunas Clinics. Conservative management was

initiated, including intravenous antibiotics, fluid

resuscitation, proton pump inhibitors, and

analgesics. During hospitalization, the patient's

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condition gradually improved—she remained

afebrile, tolerated oral intake well, and resumed

bowel movements. Inflammatory markers

showed positive downward trends. The case was

discussed in a multidisciplinary team meeting,

and due to the complex and persistent pathology,

a planned surgical intervention—laparoscopy

with right hemicolectomy—was recommended.

Figure 1. Right lower quadrant infiltrate with

air, cecal wall edema and fluid collections, small

bowel dilation.

Less than a month after hospital discharge, the

patient was brought to the emergency

department by family members in a wheelchair

due to a sudden onset of severe right leg

weakness and immobility, which had progressed

over two days. She reported an inability to walk

or move the leg, which had become cold and

discolored, with visible hematomas. On

examination, the patient was unable to stand,

transfer, or ambulate independently. The right

lumbar and hip regions were tender on palpation,

and no active movements were possible in the

right leg, with passive movements eliciting pain.

The right foot and lower leg below the mid-calf

were cyanotic and cold, with severely prolonged

capillary refill time (>8 seconds), absent distal

pulses, impaired sensation, and no resistance or

voluntary motion at the ankle joint. The limb was

flaccid, and palpation of the calf revealed

complete numbness. In contrast, the left leg had

intact circulation, palpable distal pulses, and

preserved motor and sensory function. Spiral CT

angiography of the abdominal aorta and lower

extremities (figure 2) revealed a right-sided

vascular occlusion: the external iliac artery was

occluded proximally with only a brief segment

of partial distal filling, followed by complete

cessation of contrast flow. Thrombotic material

extended into the common femoral artery, which

only filled distally before bifurcation. The

popliteal artery was completely occluded, with

no contrast opacification of the lower leg

arteries. Several fluid-gas collections and air

pockets were also visualized in the right thigh

and pelvis, consistent with necrotizing soft tissue

infection. Based on the findings of critical limb

ischemia with necrotizing fasciitis, the patient

was urgently taken to the operating room for a

high above-knee amputation. During surgery, an

incision was made in the upper third of the right

thigh. The femoral artery in the anterior-medial

compartment was ligated, and neurolisis of the

femoral and sciatic nerves was performed with

lidocaine. The tissues proximal to the

amputation site appeared viable with preserved

perfusion; mild edema was noted in the posterior

thigh, but no necrosis. Histological examination

of the amputated limb confirmed necrotizing

fasciitis, with findings including epidermal

atrophy, obliterated and thrombosed small

arteries, minor perineural thickening, skeletal

muscle fiber atrophy with fibrosis, degenerative

nuclear atypia without mitotic activity, and intra-

muscular air pockets. Postoperatively, the

patient showed clinical improvement with

declining inflammatory markers. With her

condition stabilized, she was discharged for

continued outpatient care.

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Figure 2. CT angiography of lower extremities.

Right-sided necrotizing fasciitis.

The patient reported no active complaints but

noted that during rehabilitation, inflammatory

markers were observed to be increasing, with

redness and oozing at the stump site. Laboratory

tests revealed a rising CRP (from 120 to 151

mg/L), decreasing hemoglobin levels (from 79 to

74 g/L), and malodorous discharge from the

stump area. On examination, the abdomen was

soft and non-tender. The right leg stump showed

redness along the sutures, was mildly tender, but

without significant swelling. A bedside

ultrasound, revealed a localized fluid collection

medially, though it was unclear whether this

represented residual or new changes. A

subsequent CT scan of the abdomen and pelvis,

demonstrated a 3.0 x 3.8 cm infiltrate in the

ileocecal region with thickened cecal and

ascending colon walls (up to 1.5 cm),

inflammatory changes in surrounding fat, and a

fluid collection within the iliopsoas area (up to

3.0 cm thick and 9.1 cm long) in direct continuity

with the cecal wall. Additional smaller fluid

collections with air inclusions suggested

localized perforation, with signs of involvement

of the abdominal wall. Compared to prior

imaging, the findings indicated disease

progression, now with signs of perforation.

Based on these findings, surgical intervention

was deemed necessary. During laparoscopic

exploration, a firm, fixed mass was identified in

the ileocecal area, prompting conversion to

laparotomy. The mass had perforated into the

abdominal wall and was adherent to the small

intestine. A right hemicolectomy with segmental

small bowel resection was performed. Further

revision revealed adhesions in the right iliac

fossa without macroscopic metastases. The mass

was found to involve the right ovary, fallopian

tube, and small bowel, with an additional

mucosal defect 2 meters from the Treitz ligament

and 1 meter from the ileocecal valve, suspected

to be of neoplastic origin. A 15 cm segment of

the distal ileum along with the right colon was

resected. The resected segment was sent for

histopathological analysis. Histology revealed

an infiltrative, ulcerated adenocarcinoma of the

colon (pT4b N0 Mx, LVI0, R0, G2) extending

into the resected ileal segment. The final

diagnosis was malignant neoplasm of the

ascending colon. The patient responded to

treatment with meropenem, with decreasing

inflammatory markers and good primary wound

healing, albeit with some persistent wound

discharge. She was discharged for further

outpatient care in a stable condition.

Three weeks later the patient presented with

complaints of general weakness and pain

localized to the right iliac region. She reported

the onset of fever up to 38°C, without associated

nausea, vomiting, or changes in bowel or urinary

habits. A contrast-enhanced CT scan revealed

postoperative changes following a right

hemicolectomy. In the right iliac fossa, a poorly

defined fluid collection with air inclusions was

identified, consistent with an abscess,

accompanied by significant surrounding

inflammation involving the adjacent iliopsoas

muscle, right abdominal wall, and retracted right

ureter, with upstream hydronephrosis. There was

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also concern for a fistulous connection to the

postoperative anastomosis. Fistulography

demonstrated a non-homogeneous, air-

containing fluid cavity in the right iliac region,

draining into the collection bag, though no

definitive communication with the intestinal

tract could be visualized. Given the findings, the

patient was taken to surgery, where a right-sided

pararectal incision was made. The abscess was

opened, yielding a large amount of purulent

material, which was aspirated and sent for

culture. The abscess cavity was thoroughly

irrigated. Culture results confirmed the presence

of Bacteroides fragilis, sensitive to

metronidazole, and appropriate antimicrobial

therapy was initiated. The patient later returned

for follow-up evaluation after intra-abdominal

abscess drainage. On examination, the abdomen

was soft and non-tender. The transrectal incision

had fully healed, and sutures were removed. The

overall clinical trajectory was favorable, with

clear improvement. With her postoperative

recovery stabilized and inflammatory markers

reduced, the patient was deemed fit to begin

systemic oncological treatment. She has since

commenced adjuvant chemotherapy with a

Capecitabine-based regimen: Capecitabine 2500

mg/m²/day for 14 days, with cycles repeated

every 21 days. Currently, the patient is tolerating

chemotherapy well. Her clinical condition is

stable, and she continues to show gradual

improvement. There are no signs of recurrent

infection or disease progression. Her wounds

have healed appropriately, and she is under close

oncological follow-up as outpatient.

3. Discussion

The present case illustrates an uncommon but

clinically significant complication of colon

cancer—necrotizing fasciitis arising from an

intra-abdominal abscess. While abscesses and

fistulas are known complications of advanced

CRC, their progression into necrotizing fasciitis

is exceedingly rare (3). Most documented cases

involve perforated tumors of the cecum or

sigmoid colon, with bacterial contamination

leading to fascial plane infection (14,15). In this

case, the iliopsoas involvement and spread into

surrounding tissue exemplify the aggressive

nature of such infections.

The pathophysiology of NF in colorectal cancer

involves tumor-induced necrosis or perforation

creating a conduit for enteric microorganisms,

particularly anaerobes like Bacteroides fragilis,

to invade sterile tissue compartments. The

presence of immunosuppression—whether

cancer-related, treatment-induced, or due to age

and comorbidities—further accelerates disease

progression (8). The identification of

Bacteroides fragilis in the intra-abdominal

abscess supports the theory of enteric seeding, a

common mechanism in cancer-associated NF.

Management hinges on early recognition and

prompt, aggressive surgical debridement, which

is essential to control the spread of infection and

reduce mortality (16). In this case, timely

surgical drainage of the abscess, removal of

necrotic tissue, and the use of targeted

antimicrobial therapy resulted in clinical

improvement, allowing for subsequent

chemotherapy initiation. Literature supports that

the combination of early surgical intervention

and appropriate antibiotics is crucial for patient

survival (17).

While NF remains rare in colorectal cancer, this

case emphasizes the need for vigilance when

dealing with complex intra-abdominal infections

in cancer patients. Delays in diagnosis or

inadequate treatment can result in catastrophic

outcomes. This report contributes to the limited

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body of literature and encourages further

documentation and study of such cases to better

understand their pathogenesis, optimize

management strategies, and improve

prognostication.

4. Conclusion

This case highlights a rare but life-threatening

presentation of necrotizing fasciitis secondary to

advanced colorectal cancer. Although colorectal

cancer is a common malignancy, its progression

to perforation, fistula formation, and necrotizing

soft tissue infection is exceedingly uncommon

and often underdiagnosed. The case underscores

how tumor-related anatomical disruptions can

provide a pathway for polymicrobial invasion

into deep fascial planes, with devastating

consequences if not swiftly addressed.

Successful management required prompt

imaging, emergent surgical debridement,

targeted antimicrobial therapy, and collaborative

care involving surgeons, infectious disease

specialists, and oncologists. This approach not

only salvaged the patient from an otherwise fatal

infection but also allowed for eventual oncologic

treatment, demonstrating the potential for

favorable outcomes even in complex clinical

scenarios.

Clinicians must maintain a high index of

suspicion when encountering soft tissue

infections in patients with known or suspected

malignancies, particularly when accompanied

by atypical abdominal or musculoskeletal

symptoms. This case contributes to a limited

body of literature on cancer-associated

necrotizing infections and advocates for early

imaging, aggressive management, and enhanced

vigilance in high-risk patients to improve

survival and preserve long-term function.

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Colon Cancer complicated by intrabdominal abscess and necrotizing fasciitis – a case report