Comparative evaluation of neonatal bilirubin using Radiometer whole blood co-oximetry and plasma bilirubin methods from Roche Diagnostics and Ortho Clinical Diagnostics.

BACKGROUND: Clinically significant variation has been reported within and between plasma and whole blood total bilirubin methods used to identify neonates for whom clinical intervention for hyperbilirubinemia may be required. OBJECTIVE: To evaluate total bilirubin measurements between the Radiometer whole blood co-oximeter and plasma bilirubin methods from Roche Diagnostics and Ortho Clinical Diagnostics using neonatal specimens. METHODS: Total bilirubin levels were analyzed by whole blood co-oximetry (Radiometer® ABL90). Specimens were centrifuged and plasma analyzed for total bilirubin with a diazo method (Roche Cobas® C-601) and a reflectance spectrophotometric BuBc dry film method (Ortho Clinical Diagnostics VITROS® 350). Results were evaluated by regression, Bland-Altman comparisons and t-tests. RESULTS: The patient correlation study yielded the following regression equations in µmol/L: a) Radiometer=1.03 Roche - 3.5µmol/L b) Radiometer=0.98 Ortho - 5.7µmol/L c) Roche=0.97 Ortho - 2.4µmol/L. The mean bias over the range of total bilirubin levels examined was -1.0µmol/L for the Radiometer versus the Roche (p≤0.305); -4.4µmol/L for the Radiometer versus Ortho (p≤0.005) and -4.4µmol/L for the Roche versus Ortho (p≤0.002). CONCLUSIONS: Whole blood total bilirubin measurement using the Radiometer ABL90 blood gas analyzer provides accurate and precise results compared to the Roche plasma diazo method. Compared to the reflectance spectrophotometric method, results are precise and had a small but statistically significant bias of -4.4µmol/L.

Primary large cell neuroendocrine carcinoma of the skin: An under-recognized entity and a mimic of metastatic disease.

Primary large cell neuroendocrine carcinomas of the skin are exceptionally rare and can be diagnosed only when a metastasis from another organ has been excluded. We report the case of a 62-year-old woman with a cutaneous papule on the mid-chest which generated a differential diagnosis of vascular lesion and basal cell carcinoma. Following excision, microscopic evaluation revealed a dermal large cell undifferentiated carcinoma, with a brisk mitotic rate and focal geographic necrosis. Mucin production was absent. On immunohistochemistry, the lesion expressed CK7, AE1AE3, CK8/18, chromogranin, synaptophysin, CD56, calcitonin (patchy) and TTF-1 (minimal focal). Stains for neurofilament, CK20, CK5/6, p40, p63, SOX10, MART-1, EMA, CEA, ER/PR, GATA3, GCDFP, mammoglobin, PAX-8, CDX2, napsin, ERG and MCPyV proved negative. The histopathological diagnosis was of a large cell neuroendocrine carcinoma, probably metastatic. The patient underwent comprehensive clinical, laboratory and radiographic investigations and no underlying primary carcinoma was detected. During a 20-month follow-up period with an oncologist, the patient remains well and free of any apparent carcinoma. This suggests a primary large cell neuroendocrine carcinoma of skin. To date, 3 such cases have been reported in Japanese patients. This is the first in a Caucasian resident of North America.

AL Amyloidoma of the Skin/Subcutis: Cutaneous Amyloidosis, Plasma Cell Dyscrasia or a Manifestation of Primary Cutaneous Marginal Zone Lymphoma?

It is unclear whether AL amyloidoma of the skin/subcutis represents a distinct entity, an indolent precursor of systemic amyloidosis, or a manifestation of cutaneous marginal zone lymphoma (cMZL). We collected 10 cases of cutaneous AL amyloidoma in order to better characterize the clinicopathologic features of this elusive entity (M:F=4:6; median age: 62.5 y, range: 31 to 82 y). Nine patients had a solitary nodule or plaque on the lower extremity (n=7), upper extremity (n=1), or chin (n=1). One patient had an AL amyloidoma on the right thigh and a second lesion on the right arm showing histopathologic features of cMZL without amyloid deposits. Clinical investigations excluded relevant systemic disease in all cases. Microscopically, dermal/subcutaneous deposits of amyloid were associated with sparse to moderate perivascular infiltrates of lymphocytes and monotypic plasma cells (7 with kappa and 3 with lambda light chain restriction). The plasma cells expressed CD56 in one of 9 studied cases. One case was characterized by a t(14;18)(q32;q21)/IGH-MALT1 translocation. Follow-up was available in 8 cases. All remain systemically well after a median time of 86.5 months (range: 40 to 144 mo). Local recurrence of disease was observed in 3 patients. A fourth patient presented with a cMZL without amyloid deposits 8 years after excision of the cutaneous AL amyloidoma. Although our series is small, careful categorization and follow-up of the cases, together with updated information in the literature, show clinical and biological links between AL amyloidomas of the skin/subcutis and cMZL, suggesting that at least a subset of cutaneous AL amyloidoma may represent an unusual manifestation of cMZL (cutaneous mucosa-associated lymphoid tissue lymphomas).