A pt. has a pituitary tumour and pheochromocytoma and a thyroid nodule. Which Ca is most likely to occur -
This pt. is suffering from MEN Syndrome.
MEN (Multiple endocrine neoplasias) or MEA (Multiple endocrine adenomatosis) syndromes are characterized by the familial occurrence of multiple endocrine neoplasms.
3 types of MEN Syndrome are recognized.

a) MEN I (or Wermer's Syndrome*) consists of -

Pituitary adenoma (or hyperplasia)*
Parathyroid adenoma (or hyperplasia)*
Pancreatic islet cell hyperplasia, adenoma or carcinoma 

Other less common manifestations :

foregut carcinoids
pheochromocytoma
subcutaneous or visceral lipomas

b) MEN HA ( or Sipple syndrome)

Medullary carcinoma of thyroid (MCT)*
Pheochromocytoma*
Parathyroid adenoma (or hyperplasia)*
Hirschsprung disease*
Cutaneous lichen amyloidosis*


c) MEN H B

Medullary carcinoma of thyroid (MCT)*
Pheochromocytoma *
Marfanoid features*
Mucocutaneous and gastrointestinal neuromas*
Thus this pt. is suffering from MEN II A or II B syndrome (Pituitary tumor in this pt. is still confusing the question, but still; answer is definitely MCT).
Follicular Ca
Medullary Ca
Papillary Ca
Anaplastic Ca