Sinus histiocytosis: It is seen in lymph nodes draining limbs, inflammatory lesions, and malignancies. Nodal extensive necrosis
Nodal granulomatous inflammation
Nodal extensive fibrosis (Connective tissue framework)
Nodal deposition of interstitial substanceThese morphological patterns are never pure. Thus, reactive follicular hyperplasia can have a component of paracortical hyperplasia. However, this distinction is important for the differential diagnosis of the cause. Diagnosis
In cervical lymphadenopathy (of the neck),  it is routine to perform a throat examination including the use of a mirror and an endoscope.On ultrasound, B-mode imaging depicts lymph node morphology, whilst power Doppler can assess the vascular pattern. B-mode imaging features that can distinguish metastasis and lymphoma include size, shape, calcification, loss of hilar architecture, as well as intranodal necrosis. Soft tissue edema and nodal matting on B-mode imaging suggests tuberculous cervical lymphadenitis or previous radiation therapy. Serial monitoring of nodal size and vascularity are useful in assessing treatment response.Fine needle aspiration cytology (FNAC) has sensitivity and specificity percentages of 81% and 100%, respectively, in the histopathology of malignant cervical lymphadenopathy. PET-CT has proven to be helpful in identifying occult primary carcinomas of the head and neck, especially when applied as a guiding tool prior to panendoscopy, and may induce treatment related clinical decisions in up to 60% of cases. Classification
Lymphadenopathy may be classified by:

Size, where lymphadenopathy in adults is often defined as a short axis of one or more lymph nodes is greater than 10mm.
Lymphadenopathy or adenopathy is a disease of the lymph nodes, in which they are abnormal in size or consistency. Lymphadenopathy of an inflammatory type (the most common type) is lymphadenitis,  producing swollen or enlarged lymph nodes. In clinical practice, the distinction between lymphadenopathy and lymphadenitis is rarely made and the words are usually treated as synonymous. Inflammation of the lymphatic vessels is known as lymphangitis. Infectious lymphadenitis affecting lymph nodes in the neck is often called scrofula. Lymphadenopathy is a common and nonspecific sign. Common causes include infections (from minor causes such as the common cold and post-vaccination swelling to serious ones such as HIV/AIDS), autoimmune diseases, and cancer. Lymphadenopathy is frequently idiopathic and self-limiting. Causes
Lymph node enlargement is recognized as a common sign of infectious, autoimmune, or malignant disease. Examples may include:

Reactive: acute infection (e.g., bacterial, or viral), or chronic infections (tuberculous lymphadenitis, cat-scratch disease). The most distinctive sign of bubonic plague is extreme swelling of one or more lymph nodes that bulge out of the skin as "buboes." The buboes often become necrotic and may even rupture. Infectious mononucleosis is an acute viral infection usually caused by Epstein-Barr virus and may be characterized by a marked enlargement of the cervical lymph nodes. It is also a sign of cutaneous anthrax and Human African trypanosomiasis
Toxoplasmosis, a parasitic disease, gives a generalized lymphadenopathy (Piringer-Kuchinka lymphadenopathy).