ABSTRACT
The assumption in a patient with a history of melanoma is that any subsequent lymphadenopathy is metastatic disease. We present a case where a seemingly obvious case of metastatic malignant melanoma proved to be Reactive Follicular Hyperplasia, illustrating it is important to be aware of all differential diagnoses, even when a cause appears obvious.
Subject(s)
Leg/pathology , Lymphoproliferative Disorders/pathology , Lymphoproliferative Disorders/surgery , Biopsy , Diagnosis, Differential , Female , Humans , Hyperplasia/pathology , Melanoma/pathology , Middle Aged , Skin Neoplasms/pathologyABSTRACT
AIM: After a misdiagnosis of pulmonary adenocarcinoma as desquamative interstitial pneumonia (DIP), we investigated whether immunohistochemical markers could differentiate these conditions. METHODS AND RESULTS: Three cases of DIP and one pulmonary adenocarcinoma masquerading as DIP were studied by light and electron microscopy. All cases were mucin-negative. The cases of DIP were CD68 positive but cytokeratin-negative. The adenocarcinoma was cytokeratin-positive (AE1/3 and CAM5.2), as well as showing some CD68-positive cells. Markers for carcinoma (CEA, Ber-EP4, and Leu M1) were negative in all cases. Ultrastructurally the adenocarcinoma appeared to be derived from Type II pneumocytes. CONCLUSION: Before a diagnosis of DIP is made, cytokeratin markers should be used.
