This is the 20th case in our series of “Can you solve this case?” posts. These cases are a nice low-stress way to test your path knowledge. Take a look at the question and photo, and then see if you can answer before scrolling down to see the answer and explanation.

A 60-year-old male with multiple peripheral lung nodules undergoes lung biopsy. A representative section is shown here.

Unknown 20

What is the diagnosis?

A. Squamous cell carcinoma
B. Papillary adenocarcinoma
C. Adenocarcinoma in situ
D. Small cell carcinoma
E. Large cell carcinoma

 

 

 

 

(Scroll down for the answer)

 

 

 

 

 

 

 

The diagnosis in this case is adenocarcinoma in situ (which used to be called bronchioloalveolar carcinoma). This type of lung cancer usually occurs in the peripheral portions of the lung. It often takes the form of multiple, diffuse nodules which may give the appearance of a pneumonia-like consolidation on chest xray and even on gross examination.

Microscopically, the tumor cells grow along alveolar septae without invasion into surrounding tissue or blood vessels. As you might expect from the name, the prognosis is better for adenocarcinoma in situ than it is for other types of lung carcinoma, particularly in cases which present as a single nodule.

If you liked this case, and want to test yourself with other unknown cases, here are some to try:

  • Case 1: 20-year-old male who died suddenly
  • Case 2: 72-year-old male with right calf mass
  • Case 3: 67-year-old female with pancytopenia
  • Case 4: 59-year-old male with severe headaches
  • Case 5: 38-year-old female with deep venous thrombi
  • Case 6: 13-year-old male with cerebellar mass
  • Case 7: 45-year-old male with pulmonary emphysema
  • Case 8: 38-year-old male with AIDS and headaches
  • Case 9: 25-year-old male with arm mass
  • Case 10: 57-year-old male with fatigue and left upper quadrant heaviness
  • Case 11: 62-year-old male with hepatosplenomegaly, skin lesions and cardiomyopathy
  • Case 12: 16-month-old infant with failure to thrive
  • Case 13: 36-year-old female with painless lower leg nodule
  • Case 14: 58-year-old female with several-year history of pelvic pain
  • Case 15: 52-year-old male with abdominal pain and bloody diarrhea
  • Case 16 : 42-year-old female with tinnitus, hearing loss, and a mass at the cerebellopontine angle
  • Case 17 : 52-year-old male with HIV with profuse, watery diarrhea
  • Case 18: 44-year-old male with history of progressive weakness and visual changes
  • Case 19: 20-year-old male with large, deep thigh mass