•  71yo F with PMHx of HTN, T2DM, GERD, and CVA
  • 10 years ago showed multiple pulmonary nodules measuring up to 8 mm, none of which were avid on PET/CT
  • 5 years later repeat PET/CT showed new uptake in several nodules (previously none of which showed any uptake).
  • 1 year later Repeat PET/CT showed several lung nodules that were mildly avid including 2 LUL and 1 RML nodule. The RML nodule in particular was the most avid (SUVmax 12)
  • sampled by IR but came back as benign lung parenchyma

Nodules appear to be bronchocentric

.

• Lung Nodules – DPNLH:
• 71F asymptomatic patient noted to have pulmonary nodules followed over 16 years via CT. A nodule in the right middle lobe (RML) increased in size from 4 mm to 9 mm and became PET avid, while other nodules remained stable and PET negative. Most likely diagnosis: DPNLH.
• Comment : The slow growth over time and selective PET avidity are key findings that help differentiate this condition from malignancy.
• Source: Ashley Davidoff, TheCommonVein.com, b12424-03c.1k.

 

1. Diffuse Pulmonary Nodular Lymphoid Hyperplasia (NLH)

  • Rare benign lymphoproliferative disorder.
  • Characterized by multiple bronchocentric nodules that are slow-growing.
  • Typically seen in elderly women.
  • Predominantly affects the lower lobes.
  • Histologically consists of reactive lymphoid tissue centered around bronchi.
  • Often an incidental finding and may be asymptomatic.
Basal and Peripheral Subpleural Nodules    A 71-year-old asymptomatic female with multiple pulmonary nodules followed over 16 years via CT imaging. Images show multiple nodules in a peripheral subpleural location. One of the nodules demonstrates a central lucency, likely reflecting a bronchocentric nature (red arrowhead). The distribution of nodules follows a linear perilymphatic pattern, either along the bronchovascular bundles or the venules (bcd), consistent with lymphatic distribution.(Image Source: Ashley Davidoff, TheCommonVein.com, Case ID: b12424-06L)
Basal and Peripheral Subpleural Nodules
A 71-year-old asymptomatic female with multiple pulmonary nodules followed over 16 years via CT imaging. Images show multiple nodules in a peripheral subpleural location.                            One of the nodules demonstrates a central lucency, likely reflecting a bronchocentric nature (red arrowhead). The distribution of nodules follows a linear perilymphatic pattern, either along the bronchovascular bundles or the venules (bcd), consistent with lymphatic distribution.(Image
Source: Ashley Davidoff, TheCommonVein.com, Case ID: b12424-06L)
Title: RML Growing Nodule – PET Scan
A 71-year-old asymptomatic female with multiple pulmonary nodules followed over 16 years via CT imaging. The right middle lobe (RML) nodule, initially 4 mm, increased to 9 mm over 10 years. The CT scan (left image) shows the nodule, while the PET scan (right image) demonstrates FDG avidity, suggesting metabolic activity. The most likely diagnosis is Diffuse Pulmonary Nodular Lymphoid Hyperplasia (DPNLH).
(Image Source: Ashley Davidoff, TheCommonVein.com, Case ID: b12424-05)

Diffuse Idiopathic Pulmonary Neuroendocrine Cell Hyperplasia (DIPNECH)

  • Bronchocentric? Yes, strongly bronchocentric.
  • What is it? A rare preinvasive neuroendocrine proliferation affecting the small airways.
  • CT Findings:
    • Multiple small nodules (<5mm), often centrilobular and peribronchiolar.
    • Air trapping on expiratory CT (due to small airway obstruction).
    • Mosaic attenuation (due to functional lung trapping).
    • May progress to carcinoid tumors.
  • PET Avidity? Can be mildly PET avid, especially if progressing to carcinoid tumors.
  • Demographic? Most commonly affects middle-aged to elderly women.
  • Clinical Clue? Often presents with chronic cough and dyspnea mimicking bronchiolitis or COPD.

✅ DIPNECH is strongly bronchocentric, affecting the bronchioles and leading to nodular hyperplasia.

2. Diffuse Pulmonary Meningotheliomatosis (DPM)

  • Bronchocentric? Not typically, more pleural/subpleural.
  • What is it? A rare, benign proliferation of meningothelial-like cells (MLCs) in the lungs.
  • CT Findings:
    • Multiple small subpleural nodules (diffuse or along interlobular septa).
    • No clear bronchocentric distribution.
    • No strong association with airway changes.
  • PET Avidity? Typically not PET avid.
  • Demographic? Predominantly in middle-aged women, often an incidental finding.
  • Clinical Clue? Usually asymptomatic or mild nonspecific respiratory symptoms.

❌ DPM is not typically bronchocentric; it is more interstitial and subpleural.

Final Thoughts:

  • DIPNECH → Strongly bronchocentric (small airways, centrilobular nodules, air trapping).
  • DPM → Not bronchocentric (more subpleural and interstitial).
  • Your Case: Given lower lobe predominance and PET avidity, DIPNECH is less likely (usually diffuse, centrilobular, and upper lobe-predominant). DPM is unlikely due to its lack of PET avidity and bronchocentric involvement.

Reference b12424

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