Buttock Pain: Could It Be Cancer? Causes, Red Flags & When to See a Doctor

Can Buttock Pain Be Caused by a Tumor?

While uncommon, several types of tumors can produce pain in the buttock region, either by directly involving the gluteal muscles, bones, or nerves, or by exerting pressure on adjacent structures.

Soft Tissue Sarcomas

Soft tissue sarcomas are rare malignant tumors that develop from the body’s connective tissues, including muscles, fat, nerves, blood vessels, and deep skin tissues. They account for less than 1% of all malignant tumors in adults.

When they arise in or near the gluteal region, their clinical presentation may include:

• A persistent, progressive pain in the buttock, often the initial symptom
• A growing, palpable mass in the gluteal area;
• Pain present at rest or at night (an important red flag);
• Possible neurological symptoms if the tumor compresses adjacent nerves.

Key features that should raise suspicion: a painless or mildly painful soft tissue mass larger than 5 cm, or any deep soft tissue mass regardless of size, should be referred for urgent imaging and specialist evaluation.

Bone Metastases

Bone metastases to the pelvis, sacrum, or proximal femur occur more often than primary bone tumors. They are predominantly seen in patients with a known history of cancer, most frequently from the following sources.

• Breast cancer
• Prostate cancer
• Lung cancer
• Colorectal cancer

Anecdotal cases in the literature also document less common primary tumors metastasizing to the gluteal region. For example, an esophageal adenocarcinoma metastasizing to the gluteal musculature has been reported (link).

The pain associated with bone metastases is characteristically:

• Constant and progressive, worsening steadily over weeks to months
• Present at night and at rest (unlike mechanical pain, which is typically activity-related);
• Poorly responsive to simple analgesics in advanced cases.

Sacral Chordoma

A sacral chordoma is a rare, slow-growing malignant tumor arising from remnants of the embryonic notochord within the sacral bone. While rare, it represents the most common primary malignant tumor of the sacrum.

Clinical features include:

• Chronic, deep, aching buttock and sacral pain (often present for months before diagnosis due to the tumor’s slow growth)
• Neurological deficits: bowel or bladder dysfunction, sensory changes, or weakness in the lower limbs (as the tumor enlarges and compresses sacral nerve roots);
• A palpable presacral mass on rectal examination in advanced cases.

For more information, see the dedicated resource from the Milan Cancer Institute (Istituto Tumori Milano).

Neurogenic Tumors

Tumors arising from peripheral nerve sheaths, particularly schwannomas and neurofibromas, can develop along the sciatic nerve as it traverses the greater sciatic foramen and passes through or near the piriformis muscle.

These tumors may cause:

• Neuropathic pain in the buttock, often described as burning, electric, or lancinating
• Radiation of pain down the posterior thigh and leg (mimicking sciatica);
• Progressive sensory and motor deficits in the distribution of the sciatic nerve;
• A palpable mass along the course of the nerve in some cases.

The clinical picture can closely resemble classical lumbar disc herniation, making MRI essential for differentiation.

Tumor-Induced Piriformis Syndrome

In particularly rare clinical scenarios, a pelvic tumor may exert mass effect on the piriformis muscle, triggering piriformis syndrome, a condition characterized by buttock pain and sciatic nerve irritation due to piriformis muscle spasm or hypertrophy. This mechanism has been documented in the literature, for example in cases of pelvic tumors compressing the piriformis and secondary sciatic nerve irritation.

In these cases, the buttock pain is secondary. It results not from direct tumor invasion of the gluteal region but from the indirect mechanical effect of the tumor on adjacent neuromuscular structures.

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Could It Be Colon Cancer?

Yes, in rare cases, buttock pain can be a manifestation of metastatic colorectal cancer.

A documented case in the medical literature describes a patient who developed severe right buttock pain two years after partial colectomy for sigmoid colon cancer. Imaging revealed a soft tissue mass with calcification in the gluteal musculature, which was subsequently proven by biopsy to be an ossifying intramuscular metastasis from the original colorectal primary. This case illustrates that, while exceedingly rare, hematogenous metastasis to the gluteal muscles can occur in colorectal cancer, particularly in patients with a known prior history of the disease.

A similarly instructive case was published in BMJ Case Reports, describing a patient who developed a metastatic deposit in the piriformis muscle. The metastasis originated from a previously removed rectal polyp, a lesion initially considered low-risk. This case underscores that even tumors initially assessed as low-grade can, on rare occasions, produce distant metastases with an unusual clinical presentation.

Key clinical implication: In any patient with a history of colorectal cancer who develops new, unexplained buttock pain, particularly pain that is constant, progressive, and unrelated to activity, metastatic disease to the pelvis, sacrum, or gluteal musculature should be included in the differential diagnosis and appropriate imaging should be performed.

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Could It Be Anal Cancer?

Anal cancer is a relatively uncommon malignancy, accounting for approximately 2–3% of gastrointestinal cancers. While it can cause pain in the perianal and gluteal region, it is typically accompanied by more specific symptoms that direct clinical attention toward the anorectal area:

• Rectal bleeding (the most common symptom, present in approximately 45% of patients)
• Blood in stool;
• Perianal itching or discharge;
• A palpable lump or mass at the anal margin;
• Changes in bowel habits.

Isolated gluteal pain without these accompanying anorectal symptoms would be an atypical presentation of anal cancer. However, locally advanced anal tumors can extend into adjacent structures (ischiorectal fossa, gluteal musculature, sacrum) and cause pain that radiates into the buttock. Any persistent perianal or gluteal symptoms, particularly with associated rectal bleeding, warrant colorectal surgical or gastroenterological evaluation.

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When Should You Be Concerned? Red Flag Symptoms

The vast majority of buttock pain is benign and resolves with conservative treatment. However, certain clinical features, known as “red flags”, should prompt urgent medical evaluation to exclude serious pathology, including malignancy:

If you experience buttock pain accompanied by one or more of these red flags, particularly progressive neurological symptoms or bowel/bladder dysfunction, seek urgent medical evaluation. Do not wait for the pain to resolve spontaneously.**

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Diagnosis

When a physician evaluates a patient with buttock pain, particularly in the presence of red flags or when the pain fails to respond to initial conservative management, the diagnostic workup typically follows a structured approach:

Detailed Medical History (Anamnesis)

The medical history is the most important first step. The physician will collect comprehensive information including:

• Character of the pain: Is it sharp, dull, burning, or aching? Is it constant or intermittent?
• Duration and progression: How long has it been present? Is it worsening, stable, or improving?
• Relationship to activity: Is it worse with movement, specific positions, or present even at rest?
• Nocturnal pain: Does it wake the patient from sleep?
• Associated symptoms: neurological changes (weakness, numbness, tingling), bowel or bladder dysfunction, rectal bleeding;
• Cancer history: any prior malignancy, its type, treatment received, and follow-up status;
• Family history: first-degree relatives with colorectal, breast, prostate, or other cancers;
• Systemic symptoms: fever, unexplained weight loss, night sweats, fatigue.

Physical Examination

A thorough physical examination should include:

• Inspection and palpation of the buttock, gluteal muscles, and surrounding structures, identifying any palpable mass, tenderness, warmth, or skin changes;
• Rectal examination: essential when anorectal or pelvic pathology is suspected; allows palpation of the posterior pelvic wall, sacrum, and presacral space;
• Hip and lumbar spine assessment: range of motion, pain provocation tests (FABER, FADIR), and straight leg raise, to differentiate gluteal pain from hip or spinal pathology;
• Neurological assessment: lower limb sensation, muscle strength, deep tendon reflexes, and assessment of saddle area sensation (S3–S5, relevant for sacral tumors);
• Assessment for piriformis syndrome (FAIR test, direct piriformis palpation).

Imaging Investigations

The choice of imaging modality depends on clinical suspicion:

X-ray (Plain Radiograph):

• First-line investigation for suspected bone pathology;
• Can identify: bone metastases (lytic or sclerotic lesions), fractures, arthritic changes, sacral or pelvic bone destruction;
• Limitations: insensitive for early bone metastases (up to 50% of trabecular bone must be destroyed before lesions are visible on X-ray) and does not visualize soft tissue masses.

Ultrasound:

• Non-invasive, radiation-free, and allows real-time dynamic assessment;
• Useful for: evaluation of superficial soft tissue masses, tendinopathy, bursitis, fluid collections, and guiding biopsy of accessible lesions;
• Limitations: limited penetration for deep pelvic or bone structures; operator-dependent.

MRI (Magnetic Resonance Imaging):

• The investigation of choice for soft tissue assessment in the buttock and pelvis;
• Provides superior contrast resolution for: muscles, nerves, bone marrow, fascial planes, and tumor characterization;
• Essential for: suspected soft tissue sarcoma, neurogenic tumors, sacral chordoma, disc herniation, and pelvic tumors with gluteal extension;
• Can differentiate benign from malignant lesions based on signal characteristics, enhancement patterns, and relationship to surrounding structures.

CT Scan (Computed Tomography):

• Excellent for: bone detail (cortical destruction, matrix mineralization), staging of known malignancy (assessing lymph nodes and distant metastases), and pre-operative planning;
• CT-guided biopsy: CT is the standard modality for guiding percutaneous biopsy of deep pelvic or osseous lesions;
• Limitations: lower soft tissue contrast resolution than MRI; involves ionizing radiation.

PET-CT (Positron Emission Tomography combined with CT):

• Used for systemic staging of known malignancy to identify the full extent of metastatic disease;
• Can detect metabolically active tumor deposits throughout the body;
• Not a first-line investigation for isolated gluteal pain but may be indicated when metastatic disease is confirmed or highly suspected.

Bone Scintigraphy:

• Sensitive (though not specific) for bone metastases, often revealing multiple lesions not yet visible on X-ray.
• May be used in patients with known cancer and new skeletal pain when CT and MRI are not immediately available.

Biopsy (In Selected Cases)

When imaging identifies a suspicious mass, particularly one with features suggesting malignancy (irregular margins, heterogeneous signal, surrounding edema, bone destruction), biopsy is essential for definitive diagnosis.

Key principles of biopsy in suspected sarcoma:

• Must be planned by an experienced multidisciplinary sarcoma team, as an incorrectly planned biopsy can compromise subsequent surgical resection and potentially worsen prognosis
• Core needle biopsy (CT- or ultrasound-guided) is generally preferred over excisional biopsy for deep lesions;
• The biopsy tract must be planned along the future surgical excision path so it can be excised en bloc with the tumor;
• The specimen is analyzed by a specialist sarcoma pathologist for histological subtype and grade.

Tumor markers (e.g., CEA, CA 19-9 for colorectal cancer; PSA for prostate cancer) may be measured in patients with a relevant prior cancer history to assist in assessing disease activity and recurrence.

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Conclusion

While it is clinically important to consider tumors in the differential diagnosis of persistent or atypical buttock pain, particularly when red flag symptoms are present, it is equally important to avoid causing unwarranted anxiety. The statistical reality is reassuring:

The overwhelming majority of buttock pain cases have benign, musculoskeletal, or neurological causes, including piriformis syndrome, gluteal tendinopathy, bursitis, sciatica from lumbar disc herniation, sacroiliac joint dysfunction, and referred pain from the hip or lumbar spine. These conditions are diagnosable and treatable.

Neoplastic causes of gluteal pain are genuinely rare, but they do exist and carry the potential for significant morbidity if diagnosis is delayed. The key message is not to alarm, but to inform:

• Acute buttock pain following activity, without red flags, in an otherwise healthy individual: very likely benign. Conservative management is appropriate.
• Persistent, progressive, or nocturnal buttock pain, especially in older patients, those with a cancer history, or those with associated systemic or neurological symptoms, warrants timely, thorough medical evaluation.

A prompt and thorough medical assessment, combining a careful history, physical examination, and appropriate imaging, is the most reliable path to an accurate diagnosis and effective treatment, whatever the underlying cause.