Resected cytokeratin-negative small cell lung carcinoma.

Small cell lung carcinoma (SCLC), a malignancy of neuroendocrine origin, can show varied morphologies and patterns but is typically positive for at least one neuroendocrine marker and almost always for cytokeratins. It is essential to distinguish this tumour due to its characteristic genetic features, aggressive behaviour, propensity for metastasis and responsiveness to chemotherapy. We hereby present a rare case of a pulmonary mass that showed morphological features of an SCLC but lacked cytokeratin expression on biopsy as well as resection specimens. Various cytokeratins were tested on multiple blocks and at different laboratories. A broad differential diagnosis was considered and ruled out including small round blue cell tumours, non-SCLC and metastasis. After performing an extensive work-up to identify the origin of this tumour, it was finally diagnosed as SCLC with expression of neuroendocrine markers synaptophysin and CD56, and intracytoplasmic electron dense neurosecretory granules (250-350 nm) however lacked cytokeratin expression.

A Case of Drug-Induced Stevens-Johnson Syndrome.

INTRODUCTION: Stevens-Johnson syndrome is a rare but consequential and often life-threatening disorder that is most often drug-induced. CASE PRESENTATION: An 81-year-old Black man presented with 5 days of dysphagia, odynophagia, and rash. He said he had begun a course of trimethoprim-sulfamethoxazole 6 days prior for a presumed urinary tract infection. Owing to the cutaneous lesions and punch biopsy findings, he was diagnosed with drug-induced Stevens-Johnson syndrome. DISCUSSION: Stevens-Johnson syndrome is associated with a relatively high mortality rate. It is most commonly drug-induced and presents with extensive erythema, erosions, and blisters throughout the body. CONCLUSIONS: Stevens-Johnson syndrome is a rare and often life-threatening disease. Early diagnosis and management is important for delivering high-quality patient care.

Undifferentiated carcinoma with osteoclast-like giant cells: A pathologic-radiologic correlation of a rare histologic subtype of pancreatic ductal adenocarcinoma.

Undifferentiated carcinoma with osteoclast-like giant cells (UC-OGC) is an exceedingly rare subtype of pancreatic ductal adenocarcinoma. Histologically, UC-OGC is characterized by three cell types namely, a neoplastic mononuclear cell component, non-neoplastic osteoclast-like giant cells, and a non-neoplastic mononuclear histiocytic component. The behavior of this tumor is unpredictable; but many patients survive many years after diagnosis. UC-OGC may have a better prognosis compared to conventional pancreatic adenocarcinoma due to its slower local spread, less aggressive nature, better response to surgical resection and/or chemotherapy, and fewer metastases. Due to likely differences in prognosis and significant impact on patient management, it is important to distinguish this subtype from other types of pancreatic adenocarcinoma. We report a case of a small (<1 cm) undifferentiated carcinoma with osteoclast-like giant cells of the posterior pancreatic body discovered incidentally on magnetic resonance image (MRI) scan of a middle-aged man. The radiologic and pathologic findings are presented along with a discussion of the differential diagnosis of this exceedingly rare entity.