Page 398 - Concise Pathology for Exam Preparation ( PDFDrive )

13 The Lung 383

• PTH causing hyperkalaemia
• Calcitonin leading to hypocalcaemia
• Gonadotrophins causing gynaecomastia
• Serotonin-inducing carcinoid syndrome

Other Systemic Manifestations of Lung Carcinoma
• Lambert–Eaton myasthenic syndrome (a rare autoimmune disorder associated with
small cell carcinoma that is characterized by muscle weakness of the limbs resulting from
an autoimmune reaction, where antibodies are formed against voltage-gated calcium
channels in the neuromuscular junction)
• Sensory type of neuropathy
• Acanthosis nigricans (brown to black, velvety hyperpigmentation of the skin usually
found in body folds)
• Leukemoid reactions
• Hypertrophic pulmonary osteoarthropathy (clinical triad of digital clubbing, arthral-
gias, and ossifying periostitis)

Prognosis
• Five-year survival rate:
• Squamous and adenocarcinoma n 10%
• Small cell carcinoma n few weeks in untreated patients
• Surgery ineffective in bronchioloalveolar carcinoma (responsive to chemotherapy and
radiotherapy)
• Solitary lesions can be removed surgically and have a better survival than multiple/
pneumonic lesions.
Neuroendocrine Tumours of Lung
1. Benign tumours
2. Carcinoids
3. Small cell carcinoma

Bronchial Carcinoids
1. Constitute 1–5% of all lung tumours
2. Patients affected are generally young
3. No relationship with smoking/environmental factors
4. They present as finger-like or spherical polypoid masses, projecting into the lumen, and
covered by mucosa. They are rarely more than 3–4 cm
5. Most carcinoids remain confined to main stem bronchus; some intraluminal masses
show infiltration into the peribronchial tissue (collar button lesion)
6. Typical carcinoids have less than 2 mitoses per 10 high power fields and absence of
necrosis while atypical carcinoids have between 2 and 10 mitoses per high power field
and foci of necrosis.

Metastatic Tumours of Lung

• The lung is the most common site for metastases for both carcinomas and sarcomas.
Local spread may occur from oesophagus and mediastinum.
• Common sources of epithelial metastases include GIT, breast, thyroid, kidney, pancreas
and liver.
• Other tumours which frequently metastasize to lungs include osteogenic sarcoma,
melanoma, leukaemia-lymphomas, neuroblastoma and Wilms tumour.
• Metastasis usually presents as multiple nodules throughout the lung substance, more
towards the periphery; when large, they are labelled canon ball metastasis. Rarely, it may
present as a solitary nodule or pneumonic consolidation.

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