Sarcoidosis
Bilateral hilar lymphadenopathy with a normal examination is typical of sarcoidosis.
Sarcoidosis
- A multisystem disease of unknown etiology characterized by noncaseating granulomatous inflammation in many tissues and organs.
- It is a diagnosis of exclusion , requiring the exclusion of other causes of noncaseating granulomas (e.g., mycobacterial/fungal infections, berylliosis).
- Bilateral hilar lymphadenopathy or lung involvement is a major finding at presentation in most cases.
- Predominantly affects adults younger than 40 years.
- High incidence in Danish and Swedish populations. In the USA, it is found in African Americans at a 10-fold higher rate than in whites.
Read this in Lung Pathology — Must-Know
What our notes say
- Bilateral hilar lymphadenopathy with a normal examination is typical of sarcoidosis. (Internal Medicine Respiratory CAT 1: 30 MCQs and 5 short answer questions)
- • Respiratory disorders are associated with skin changes e.g. acute sarcoidosis – (Examination of Respiratory system — Past Paper Questions & Answers)
- Caused by: TB, sarcoidosis, schistosomiasis, leprosy, fungal infections (General Pathology Revision: Cell Injury, Inflammation & Adaptation (MBPA 3500 Pa)
- Sarcoidosis: non-caseating granulomas; young adults; bilateral hilar lymphadenopathy with or without parenchymal disease; erythema nodosum, arthralgia, uveitis, hypercalcaemia, raised ACE; Löfgren syndrome (bilateral hilar nodes + erythema nodosum + arthralgia, good prognosis). (Interstitial Lung Diseases)
- Crohn's and short bowel cause hyperoxaluria, sarcoidosis causes hypercalcaemia, and salt raises urinary calcium. (Internal Medicine End of Semester CAT (MBChB 4): haematology and renal, 30 MCQs )
- Topics tested: pneumonia, pleural effusion, COPD, asthma, occupational lung disease, ARDS, sarcoidosis and interstitial lung disease. (Internal Medicine Respiratory CAT 1: 30 MCQs and 5 short answer questions)
Study material on Sarcoidosis
- Respiratory System Pathology 1A
- Lung Pathology — Must-Know
- Respiratory system pathology mcqs
- End Sem Cat: Respiratory Pathology: Emphysema, ARDS, Pneumoconiosis
- Internal Medicine Respiratory CAT 1: 30 MCQs and 5 short answer questions
- Medical MCQs: Chemical Pathology & Haematology Exam Review
- Interstitial Lung Diseases
- Internal Medicine End of Semester CAT (MBChB 4): haematology and renal, 30 MCQs and 3 short answers
- Cardiovascular & Respiratory Pathology: Atherosclerosis, RHD & MI Review
- General Pathology Q&A
- Respiratory System Pathology 1A — Practice Questions
- Respiratory System Pathology 1A — Practice Questions
- Respiratory System Pathology 1A — Practice Questions
- Respiratory System Pathology 1A — Practice Questions
- Respiratory Pathology
- Respiratory System Pathology 1A — Practice Questions
Practice questions on Sarcoidosis
In examining a lung biopsy from a patient with sarcoidosis, noncaseating granulomas are seen. What distinguishes noncaseating from caseating granulomas?
- Noncaseating granulomas lack epithelioid macrophages
- Noncaseating granulomas have absent central necrosis
- Noncaseating granulomas contain more neutrophils
- Noncaseating granulomas lack giant cells
- Noncaseating granulomas indicate bacterial rather than immune etiology
Answer: B. Caseating vs noncaseating refers to the presence/absence of central necrosis. Caseating granulomas (TB, some fungi) have central caseous necrosis surrounded by epithelioid macrophages and Langhans giant cells. Noncaseating granulomas (sarcoidosis, Crohn disease, foreign body reactions) have collections of epithelioid macrophages and often giant cells BUT lack the central necrotic zone. BOTH types contain epithelioid
In sarcoidosis, hypercalcemia occurs due to
- Osteolytic bone destruction by granulomas
- PTHrP secretion from activated lymphocytes
- Active vitamin D production by granuloma macrophages
- Increased renal tubular calcium reabsorption
Answer: C. In sarcoidosis, mononuclear phagocytes within granulomas produce active vitamin D (1,25-dihydroxyvitamin D), increasing intestinal calcium absorption and causing hypercalcemia. ---
Which of the following regarding sarcoidosis lymph node involvement is CORRECT?
- Lymph nodes are matted and may ulcerate like in TB
- Peripheral lymphadenopathy occurs but nodes are nonadherent
- Lymph node involvement occurs in less than 25% of cases
- Lymph nodes always show caseating granulomas
Answer: B. Sarcoidosis lymph nodes are characteristically "nonmatted" (nonadherent) and do not ulcerate — unlike tuberculosis where nodes are matted. Hilar/paratracheal nodes are enlarged in 75–90% of patients. ---
Erythema nodosum in sarcoidosis represents
- Cutaneous sarcoid granulomas on the legs
- Hallmark of acute sarcoidosis — raised tender nodules on anterior legs
- Chronic skin infiltration by noncaseating granulomas
- Subcutaneous sarcoid nodules with abundant granulomas
Answer: B. Erythema nodosum is the hallmark of acute sarcoidosis. It consists of rais