What is the differential diagnosis and management for a 24-year-old patient with cervical lymphadenopathy (lymph node enlargement), mild leukopenia (low white blood cell count), mild granulocytopenia (low granulocytes), mild monocytosis (high monocytes), and mild lymphocytosis (high lymphocytes), presenting with a 10% weight loss over 2 months, without fever, and with otherwise normal laboratory results?

Differential Diagnosis for 24-year-old with Cervical Lymphadenopathy

Single Most Likely Diagnosis

• Tuberculosis (TB): Given the chronic nature of the lymphadenopathy (2 months), mild leukopenia, and the specific pattern of lymphocyte and monocyte elevation, TB is a strong consideration. The absence of fever does not rule out TB, as it can present atypically, especially in immunocompetent individuals.

Other Likely Diagnoses

• Lymphoma: The presence of cervical lymphadenopathy, weight loss, and abnormal blood cell counts (leukopenia, elevated monocytes and lymphocytes) could suggest a lymphoproliferative disorder. Both Hodgkin and non-Hodgkin lymphoma should be considered.
• HIV Infection: Chronic lymphadenopathy, weight loss, and alterations in blood cell counts can be seen in HIV infection. The elevated monocytes and lymphocytes, along with mild leukopenia, are consistent with this diagnosis.
• Sarcoidosis: This condition can cause lymphadenopathy, and while it more commonly affects the lungs, it can present with systemic symptoms like weight loss. The lack of other systemic symptoms and normal other labs makes this less likely but still a consideration.

Do Not Miss Diagnoses

• Malignancy (other than lymphoma): Although less likely, other malignancies (e.g., metastatic cancer to the lymph nodes) could present with lymphadenopathy and weight loss. Given the potential severity, this diagnosis should not be missed.
• Infectious Mononucleosis (EBV): Although typically seen with fever and sore throat, atypical presentations can occur, especially in adults. The lymphocytosis and mild leukopenia could fit this diagnosis.
• Syphilis: In its secondary stage, syphilis can cause lymphadenopathy, weight loss, and a variety of other systemic symptoms. It's a great mimic and should be considered due to its potential for serious complications if untreated.

Rare Diagnoses

• Castleman Disease: A rare disorder that can cause lymphadenopathy, weight loss, and abnormal blood cell counts. It's less likely but should be considered if other diagnoses are ruled out.
• Kikuchi-Fujimoto Disease: A rare, self-limiting condition that causes lymphadenopathy, often with fever and night sweats, but can present atypically. It's more common in young women.
• Kimura Disease: A rare, chronic inflammatory disorder that can cause lymphadenopathy and eosinophilia. It's less common and typically presents with distinctive clinical features.

Management

1. Complete Blood Count (CBC) with Differential: Already done, showing mild leukopenia, low granulocytes, high monocytes, and lymphocytes.
2. Blood Chemistry Tests: Already reported as normal.
3. Imaging: Chest X-ray and CT scans of the neck, chest, and abdomen to evaluate the extent of lymphadenopathy and to look for other signs of disease (e.g., splenomegaly, lung lesions).
4. Lymph Node Biopsy: Essential for diagnosing lymphoma, TB, and other conditions that cause lymphadenopathy.
5. Infectious Disease Workup: Include tests for TB (e.g., PPD, Quantiferon Gold), HIV, and syphilis (RPR or VDRL).
6. Mononucleosis Spot Test or EBV Serologies: To rule out infectious mononucleosis.
7. Follow-Up: Close follow-up is necessary to monitor the patient's condition and adjust the diagnostic and therapeutic approach as needed.