Tuberculous lymphadenitis (or tuberculous adenitis) is a chronic specific granulomatous inflammation of the lymph node with caseation necrosis, caused by infection with "Mycobacterium tuberculosis" or "Mycobacterium bovis".

The characteristic morphological element is the tuberculous granuloma (caseating tubercule). This consists of giant multinucleated cells and (Langhans cells), surrounded by epithelioid cells aggregates, T cell lymphocytes and fibroblasts. Granulomatous tubercules eventually develop central caseous necrosis and tend to become confluent, replacing the lymphoid tissue.

Stages of tubercular lymphadenitis:

1. Lymphadenitis

2. Periadenitis

3. Cold abscess

4. 'Collar stud' abscess

5. Sinus

Tuberculous lymphadenitis is popularly known as collar stud abscess, due to its proximity to the collar bone and superficial resemblance to a collar stud, although this is just one of the five stages of the disease. The characteristic morphological element is the tuberculous granuloma (caseating tubercule): giant multinucleated cells (Langhans cells), surrounded by epithelioid cells aggregates, T cell lymphocytes and few fibroblasts. Granulomatous tubercules evolve to central caseous necrosis and tend to become confluent, replacing the lymphoid tissue.

Lymphadenopathy of the axillary lymph nodes can be defined as solid nodes measuring more than 15 mm without fatty hilum. Axillary lymph nodes may be normal up to 30 mm if consisting largely of fat.

Lymphadenopathy or adenopathy is disease of the lymph nodes, in which they are abnormal in size, number, 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 lymphadenitides affecting lymph nodes in the neck are often called scrofula.

The term comes from the word lymph and a combination of the Greek words , "adenas" ("gland") and , "patheia" ("act of suffering" or "disease").

Lymphadenopathy is a common and nonspecific sign. Common causes include infections (from minor ones such as the common cold to dangerous ones such as HIV/AIDS), autoimmune diseases, and cancers. Lymphadenopathy is also frequently idiopathic and self-limiting.

Tuberculous gumma (also known as a "metastatic tuberculous abscess" and "metastatic tuberculous ulcer") is a cutaneous condition characterized histologically by massive necrosis. Restated, this is a skin condition that results from hematogenous dissemination of mycobacteria from a primary focus, resulting in firm, nontender erythematous nodules that soften, ulcerate, and form sinuses.

Miliary tuberculosis is a form of tuberculosis that is characterized by a wide dissemination into the human body and by the tiny size of the lesions (1–5 mm). Its name comes from a distinctive pattern seen on a chest radiograph of many tiny spots distributed throughout the lung fields with the appearance similar to millet seeds—thus the term "miliary" tuberculosis. Miliary TB may infect any number of organs, including the lungs, liver, and spleen. Miliary tuberculosis is present in about 2% of all reported cases of tuberculosis and accounts for up to 20% of all extra-pulmonary tuberculosis cases.

Patients with miliary tuberculosis often experience non-specific signs, such as coughing and enlarged lymph nodes. Miliary tuberculosis can also present with enlarged liver (40% of cases), enlarged spleen (15%), inflammation of the pancreas (<5%), and multiple organ dysfunction with adrenal insufficiency (adrenal glands do not produce enough steroid hormones to regulate organ function). Miliary tuberculosis may also present with unilateral or bilateral pneumothorax rarely. Stool may also be diarrheal in nature and appearance.

Other symptoms include fever, hypercalcemia, chorodial tubercles and cutaneous lesions.

Firstly, many patients can experience a fever lasting several weeks with daily spikes in morning temperatures.

Secondly, hypercalcemia prevails in 16 to 51% of tuberculosis cases. It is thought that hypercalcemia occurs as a response to increased macrophage activity in the body. Such that, 1,25 dihydroxycholecalciferol (also referred to as calcitriol) improves the ability of macrophages to kill bacteria; however, higher levels of calcitriol lead to higher calcium levels, and thus hypercalcemia in some cases. Thus, hypercalcemia proves to be an important symptom of miliary tuberculosis.

Thirdly, chorodial tubercules, pale lesions on the optic nerve, typically indicate miliary tuberculosis in children. These lesions may occur in one eye or both; the number of lesions varies between patients. Chorodial tubercules may serve as important symptoms of miliary tuberculosis, since their presence can often confirm suspected diagnosis.

Lastly, between 10 and 30% of adults, and 20–40% of children with miliary tuberculosis have tuberculosis meningitis. This relationship results from myobacteria from miliary tuberculosis spreading to the brain and the subarachnoid space; as a result, leading to tuberculosis meningitis.

The risk factors for contracting miliary tuberculosis are being in direct contact with a person who has it, living in unsanitary conditions, and having an unhealthy diet. In the U.S., risk factors for contracting the disease include homelessness and HIV/AIDS.

Lymphadenopathy can occur in one or more groups of lymph nodes. Among 358 cases of Rosai–Dorfman disease that Rosai collected in a disease registry for which the location of lymphadenopathy was specified, 87.3% had cervical lymphadenopathy. Axillary, inguinal, and mediastinal lymphadenopathy are also found in Rosai–Dorfman disease.

"Lymph adenitis" or "lymph node adenitis" is caused by infection in lymph nodes. The infected lymph nodes typically become enlarged, warm and tender. A swelling of lymph nodes due to growth of lymph cells is called lymphadenopathy. Types include:

- Neck

- Cervical adenitis is an inflammation of a lymph node in the neck.

- Tuberculous adenitis (scrofula) is a tuberculous infection of the skin of the neck caused by "Mycobacterium tuberculosis". Non-tuberculous adenitis can also be caused by "Mycobacterium scrofulaceum" or "Mycobacterium avium".

- Abdomen

- Mesenteric adenitis is an inflammation of the mesenteric lymph nodes in the abdomen. It can be caused by the bacterium "Yersinia enterocolitica". If it occurs in the right lower quadrant, it can be mistaken for acute appendicitis, often preceded by a sore throat.

Accumulation of histiocytes may occur outside of lymph nodes. The most common sites of extranodal disease in Rosai's registry were skin, nasal cavity/paranasal sinuses, soft tissue, eyelid/orbit, bone, salivary glands, and central nervous system.

The symptoms of this disease vary with the site of accumulation similar to other regional tumors. For instance, accumulation in closed spaces such as the cranium can lead to poor outcomes compared to growth in the dermis of an extremity where surgical excision is possible.

Scrofuloderma (also known as "Tuberculosis cutis colliquativa") is a skin condition caused by tuberculous involvement of the skin by direct extension, usually from underlying tuberculous lymphadenitis.

Primary inoculation tuberculosis (also known as "Cutaneous primary complex," "Primary tuberculous complex," and "Tuberculous chancre") is a skin condition that develops at the site of inoculation of tubercle bacilli into a tuberculosis-free individual.

Tuberculous cellulitis is a skin condition resulting from infection with mycobacterium, and presenting as cellulitis.

Sebaceous adenitis is an inflammation of the sebaceous glands

in the skin. These glands normally produce sebum (skin oil, a lipid-rich secretion) which prevents drying of the skin.

Symptoms are similar to tuberculosis (TB), and include fever, fatigue, and weight loss. Pulmonary involvement is similar to TB, while diarrhea and abdominal pain are associated with gastrointestinal involvement.

Because the TVC's entry point usually is the site of a trauma, wound or puncture in the skin (during an autopsy, for example), the most frequent site for the wart are the hands. But it can occur anywhere in the skin, such as in the sole of the feet, in the anus, and, in the case of children from developing countries, in the buttocks and knees. This is because children from countries of high incidence of tuberculosis can contract the lesion after contact with tuberculous sputum, by walking barefoot, sitting or playing on the ground.

When recent, the skin lesion has the outside appearance of a wart or verruca, thus it can be confused with other kinds of warts. It evolves to an annular red-brown plaque with time, with central healing and gradual expansion in the periphery. In this phase, it can be confused with fungal infections such as blastomycosis and chromoblastomycosis.

Tuberculous dactylitis is a skeletal manifestation of tuberculosis, one of the commonest bacterial osteitis. It affects children more often than adults. The first radiological description of the condition is credited to Feilchenfeld in 1896; however, the first histological description was given by Rankin in 1886. Multiple bones are involved in children and usually only a single bone is involved in adults suffering from tuberculous dactylitis. Tuberculous dactylitis affects the short tubular bones of the hands and feet in children. It often follows a mild course without fever and acute inflammatory signs as opposed to acute osteomyelitis. There may be a gap of a few months to 2 to 3 years from the time of initial infection to the point of diagnosis.

Spina ventosa is the term given for tuberculous dactylitis. Nearly 85% of the patients of spina ventosa are below 6 years of age.The bones of hands are more commonly involved than those of the feet. Proximal phalanx of the index and middle fingers are the commonest sites of involvement.Up to nearly 7% of children with pulmonary tuberculosis may develop this condition. Spread to the skeletal system is believed to occur via blood and lymphatics.

"Mycobacterium avium-intracellulare" infection (MAI) is an atypical mycobacterial infection, i.e. one with nontuberculous mycobacteria or NTM, caused by "Mycobacterium avium" complex ("MAC"), which is made of three mycobacteria species, "M. avium", "M. intracellulare", and "M. chimaera". This infection causes respiratory illness in birds, pigs, and humans, especially in immunocompromised people. In the later stages of AIDS it can be very severe. It usually first presents as a persistent cough. It is typically treated with a series of three antibiotics for a period of at least six months.

"M. avium", "M. intracellulare", and "M. chimaera" are each saprotrophic organisms present in soil and water; entry into hosts is usually via the gastrointestinal tract, but also can be via the lungs.

MAC infections can cause fevers, diarrhea, malabsorption, as well as loss of appetite and weight loss, and can disseminate to the bone marrow. Therapy for MAI is typically resistant to standard mycobacterial therapies.

Tuberculosis verrucosa cutis (also known as "lupus verrucosus", "prosector's wart", and "warty tuberculosis") is a rash of small, red papular nodules in the skin that may appear 2–4 weeks after inoculation by "Mycobacterium tuberculosis" in a previously infected and immunocompetent individual.

It is so called because it was a common occupational disease of prosectors, the preparers of dissections and autopsies. Reinfection by tuberculosis via the skin, therefore, can result from accidental exposure to human tuberculous tissue in physicians, pathologists and laboratory workers; or to tissues of other infected animals, in veterinarians, butchers, etc. Other names given to this form of skin tuberculosis are anatomist's wart and verruca necrogenica (literally, generated by corpses).

TVC is one of the many forms of cutaneous tuberculosis, such as the tuberculous chancre (which results from the inoculation in people without immunity), and the reactivation cutaneous tuberculosis (the most common form, which appears in previously infected patients). Other forms of cutaneous tuberculosis are: lupus vulgaris, scrofuloderma, lichen scrofulosorum, erythema induratum and the papulonecrotic tuberculid.

It was described by René Laennec in 1826.

The initial lesion is a small subcutaneous swelling following minor trauma. Later, sinuses that discharge purulent and seropurulent exudates containing grains which are fungal colonies are formed. Destruction of deeper tissues, and deformity and loss of function in the affected limbs may occur in later stages.

Fever and headache are the cardinal features, confusion is a late feature and coma bears a poor prognosis. Meningism is absent in a fifth of patients with TB meningitis. Patients may also have focal neurological deficits.

The diagnosis of the condition is made on the basis of histological and bacteriological studies. Tuberculosis dactylitis may be confused with conditions like osteomyelitis, gout, sarcoidosis and tumors.

As in the majority of paracoccidioidomycosis cases, pulmonary involvement results in shortness of breath, a productive cough and hemoptysis, as well as general symptoms of weight loss, fever and fatigue. Visually, lesions (as pictured) are often present, most commonly on the face.

Tuberculosis cutis orificialis (also known as "acute tuberculous ulcer" and "orificial tuberculosis") is a form of cutaneous tuberculosis that occurs at the mucocutaneous borders of the nose, mouth, anus, urinary meatus, and vagina, and on the mucous membrane of the mouth or tongue.

The defining symptom of pleurisy is a sudden sharp, stabbing, burning or dull pain in the right or left side of the chest during breathing, especially when one inhales and exhales. It feels worse with deep breathing, coughing, sneezing, or laughing. The pain may stay in one place, or it may spread to the shoulder or back. Sometimes, it becomes a fairly constant dull ache.

Depending on its cause, pleuritic chest pain may be accompanied by other symptoms:

- Dry cough

- Fever and chills

- Rapid, shallow breathing

- Shortness of breath

- Fast heart rate

- Sore throat followed by pain and swelling in the joints