Lump in the Posterior Triangle of the Neck

CLINICAL DIAGNOSIS MANUAL

The posterior triangle of the neck, bordered by the posterior edge of the sternocleidomastoid muscle, the anterior edge of the trapezius muscle, and the clavicle, is a key anatomical region in the clinical evaluation of neck masses or lumps. Masses in this area can be associated with a variety of pathologies, such as infections, tumours, and systemic diseases.

A proper evaluation of these masses requires a detailed medical history, accompanied by a thorough physical examination. Additionally, specific complementary tests, such as ultrasounds, biopsies, and imaging studies, should be performed to determine the nature and origin of the lump.

Pathology	Symptoms and Clinical Signs	Diagnosis of Suspicion	Diagnosis of Confirmation
Acute Abscess	Severe pain, fever, general malaise. Fluctuant, painful mass, erythema, local warmth, possible pus drainage.	Clinical history and physical examination. Neck ultrasound: Pus collection.	Aspiration culture: Identification of the causative microorganism.
Cystic Hygroma	Painless mass, usually present from birth or early childhood. Soft, translucent, slow-growing mass.	Clinical history and physical examination. Neck ultrasound: Multilobulated cystic mass.	Magnetic resonance imaging (MRI): Assessment of the extent and characteristics of the hygroma.
Inflammation of Lymph Nodes	Neck pain, fever, systemic infection symptoms. Enlarged lymph nodes, tender on palpation, may be mobile or fixed.	Clinical history and physical examination. Full blood count: Leukocytosis.	Neck ultrasound: Reactive lymph nodes.
Lymphoma	Fatigue, weight loss, night sweats, fever. Enlarged, painless, firm, and mobile lymph nodes.	Clinical history and physical examination. Node biopsy: Initial histopathological examination.	Positron emission tomography (PET): Assessment of disease extent.
Metastasis in Lymph Nodes	Neck mass, possible weight loss, and systemic symptoms of primary malignancy. Firm, painless lymph nodes, may be adhered to adjacent structures.	Clinical history and physical examination. Node biopsy: Initial histopathological examination.	CT and MRI: Assessment of local and systemic extent.
Tuberculosis	Chronic neck pain, low-grade fever, night sweats, weight loss. Initially painless mass, may drain pus through the skin (fistula), chronic cervical lymphadenopathy.	Clinical history and physical examination. Tuberculin test (PPD): Positive.	Mycobacterium tuberculosis culture: From aspirated material. Chest X-ray: Evidence of pulmonary tuberculosis.