Primary Clear Cell Microcystic Adenoma of the Sinonasal Cavity: Pathological or Fortuitous Association?

Primary clear cell microcystic adenoma of the sinonasal cavity is rare. It has previously been described only as a VHL-associated tumour. Von Hippel-Lindau (VHL) syndrome is an inherited cancer syndrome characterised by an elevated risk of neoplasia including clear cell renal cell carcinoma (ccRCC), haemangioblastoma, and phaeochromocytoma. We describe the second reported case of a primary clear cell microcystic adenoma of the sinonasal cavity. The 39-year-old patient with VHL syndrome had previously undergone resection and ablation of ccRCC. He presented with epistaxis. Imaging demonstrated a mass in the ethmoid sinus. Initial clinical suspicion was of metastatic ccRCC. However, tumour morphology and immunoprofile were distinct from the previous ccRCC and supported a diagnosis of primary microcystic adenoma. Analysis of DNA extracted from sinonasal tumour tissue did not show loss of the wild-type allele at the VHL locus. Although this did not support tumour association with VHL disease, it was not possible to look for a loss-of-function mutation. The association of primary microcystic adenoma of the sinonasal cavity with VHL disease remains speculative. These lesions are benign but are likely to require regular surveillance. Such tumours may require repeated surgical excision.

An unusual breast mass: primary synovial sarcoma.

We describe a 54-year-old woman presenting with mastalgia and a 6 mm breast lesion on imaging. Core biopsy revealed a lesion characterised by a predominant epithelioid and a minor spindle cell component. Our differential diagnosis included intraduct papilloma/adenoma and adenomyoepithelioma. However, initial immunohistochemistry did not support these diagnoses and further immunohistochemistry raised the possibility of a synovial sarcoma. This was confirmed with the finding, using fluorescence in-situ hybridisation, of the characteristic translocation t(x; 18) (p11.2; q11.2). Establishing a diagnosis of synovial sarcoma at unusual sites may be difficult, especially when limited tissue is available, for example, within a core biopsy. In this case, immunohistochemistry was useful, but cytogenetics was the key additional investigation. It is important to consider the possibility of rare tumours when the morphological and immunohistochemical features of a lesion initially appear conflicting or inconclusive.

Squamous cell carcinoma arising in dentigerous cysts.

We present two cases of squamous cell carcinoma (SCC) arising in dentigerous cysts. Malignant transformation in dentigerous cysts is rare giving rise to diagnostic difficulties. We propose imaging at an early stage to reduce delays in diagnosis.

Excision margins in high-risk malignant melanoma.

BACKGROUND: Controversy exists concerning the necessary margin of excision for cutaneous melanoma 2 mm or greater in thickness. METHODS: We conducted a randomized clinical trial comparing 1-cm and 3-cm margins. RESULTS: Of the 900 patients who were enrolled, 453 were randomly assigned to undergo surgery with a 1-cm margin of excision and 447 with a 3-cm margin of excision; the median follow-up was 60 months. A 1-cm margin of excision was associated with a significantly increased risk of locoregional recurrence. There were 168 locoregional recurrences (as first events) in the group with 1-cm margins of excision, as compared with 142 in the group with 3-cm margins (hazard ratio, 1.26; 95 percent confidence interval, 1.00 to 1.59; P=0.05). There were 128 deaths attributable to melanoma in the group with 1-cm margins, as compared with 105 in the group with 3-cm margins (hazard ratio, 1.24; 95 percent confidence interval, 0.96 to 1.61; P=0.1); overall survival was similar in the two groups (hazard ratio for death, 1.07; 95 percent confidence interval, 0.85 to 1.36; P=0.6). CONCLUSIONS: A 1-cm margin of excision for melanoma with a poor prognosis (as defined by a tumor thickness of at least 2 mm) is associated with a significantly greater risk of regional recurrence than is a 3-cm margin, but with a similar overall survival rate.