Malignant pustules occurs in:
Pulmonary anthrax (wool-sorters’ disease):
Occurs due to inhalation of spores of B. anthracis in infectious aerosols results in rapid development of malignant pustule in the bronchus. 
This is followed by development of primary extensive necrotising pneumonia and haemorrhagic mediastinitis which is invariably fatal.
Mohan H. Textbook of pathology. Jaypee Brothers Medical Publishers; 2015. Edition 7. Page 169
Anthrax infection
Epithelioma
Melanoma
Tetanus