DDX of Mediastinal Masses + Lice-Induced Fe Deficiency Anemia??

Ok last back-post, I promise! These two entities have nothing to do with each other, but both came up in morning report!

Take Home Points: Mediastinal Masses and Iron Deficiency Anemia with Lice 

Mediastinal Mass DDX – The differential depends on whether the mass is in the anterior, middle, or posterior mediastinum

Anterior Mediastinal Mass – the terrible Ts + others

  • Thymus – thymoma, cyst, hyperplasia, carcinoma
  • (Terrible) Lymphoma
  • Germ Cell Tumor – Teratoma, seminoma, non-seminomatous GCT (choriocarcinoma, etc)
  • Intrathoracic Thyroid – substernal goiter, ectopic thyroid
  • Others: Parathyroid adenoma, hemangioma, lipoma, liposarcoma, fibroma, fibrosarcoma, Foramen of Morgagni (diaphgragm) hernia

Middle Mediastinal Mass

  • Bronchogenic cyst
  • Pericardial cyst
  • Lymphadenopathy – lymphoma, sarcoid, metastatic lung CA, etc
  • Enteric cyst
  • Esophageal tumors
  • Vascular masses and enlargement

Posterior Mediastinal Mass

  • Neurogenic tumors – neurofibroma, neurolemona, neurosarcoma, ganglioneuroma, ganglioneuroblastoma, neuroblastoma, chemodectoma, pheochromocytoma (among the 10% extra-adrenal)
  • Meningoceles
  • Thoracic spine lesions

Lice-Induced Fe Deficiency Anemia

Biologic plausibility – lice are parasitic and feed on blood from the host, heavy prolonged lice burden has been linked to Fe deficiency anemia in cattle in published veterinary reports

Does it happen in humans? – One study of 4 years of ED patients (attached here) reviewed all patients in the ED with lice infestation and severe Fe deficiency anemia (Hg <6).

  • 5 patients met these criteria – all underwent eval of GI bleed, hemolysis, other causes of blood loss. All had heavy head and body louse burden
  • 3/5 of these patients had a negative GI and other workup and Fe deficiency anemia was attributed to leeching from prolonged, severe lice infestation
  • KEY POINT: This is a diagnosis of exclusion!!! While interesting to think about, GI causes of occult blood loss are much more common and you MUST rule out malignancy or other etiology of blood loss before attributing the anemia to lice.
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One thought on “DDX of Mediastinal Masses + Lice-Induced Fe Deficiency Anemia??”

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