Bone marrow core biopsy in 508 consecutive patients with chronic myeloid leukemia: Assessment of potential value.

BACKGROUND: The diagnosis of chronic myeloid leukemia (CML) is based on characteristic clinical and laboratory findings and the presence of BCR/ABL1 in the blood and/or bone marrow (BM). The utility of BM core biopsy in the workup of patients with CML has been questioned. METHODS: The potential added value of BM biopsy versus aspiration in the workup of a single-institution series of 508 patients with CML at their initial presentation was systematically assessed. BM biopsy was considered essential when it was needed to establish the disease phase, often because blast counts derived from aspirate smears were misleading because the biopsy specimen was more representative of the disease. BM biopsy was considered helpful if it was needed for other nonessential reasons. RESULTS: In 127 patients (25%), BM biopsy was either essential (109 patients) or helpful (18 patients). Patients with accelerated-phase (AP) or blast-phase (BP) disease often required a biopsy related to essential reasons. High-grade myelofibrosis (MF) was more frequent in patients with AP/BP disease than patients with chronic-phase disease (P = .0005), and the identification of BP disease required a BM biopsy assessment in 75% of the patients (P = .001). A follow-up BM evaluation more often yielded inadequate aspirates in patients with inadequate BM aspirates at the time of their initial diagnosis. CONCLUSIONS: BM core biopsy remains valuable in the workup of 25% of patients with CML because it facilitates identification of the disease phase or MF. The initial grade of MF is associated with the disease stage and outcome after therapy. BM biopsy is, therefore, indicated for patients with CML who have AP/BP disease or other findings suggestive of progressive disease.

Assessment of BRAF V600E Status in Colorectal Carcinoma: Tissue-Specific Discordances between Immunohistochemistry and Sequencing.

Although sequencing provides the gold standard for identifying colorectal carcinoma with BRAF V600E mutation, immunohistochemistry (IHC) with the recently developed mouse monoclonal antibody VE1 for BRAF V600E protein has shown promise as a more widely available and rapid method. However, we identified anecdotal discordance between VE1 IHC and sequencing results and therefore analyzed VE1 staining by two different IHC methods (Leica Bond and Ventana BenchMark) in whole tissue sections from 480 colorectal carcinomas (323 BRAF wild-type, 142 BRAF V600E mutation, and 15 BRAF non-V600E mutation). We also compared the results with melanomas and papillary thyroid carcinomas (PTC). With the Bond method, among 142 BRAF V600E-mutated colorectal carcinomas, 77 (54%) had diffuse VE1 staining and 48 (33%) had heterogeneous staining, but 17 (12%) were negative. Among 323 BRAF wild-type colorectal carcinomas, 196 (61%) were negative, but 127 (39%) had staining, including 7 with diffuse staining. When positivity was defined as staining in ≥ 20% of tumor cells, VE1 IHC had sensitivity of 75% and specificity of 93% for BRAF V600E mutation. With the Ventana method, among 57 BRAF V600E-mutated colorectal carcinomas, 36 (63%) had diffuse VE1 staining, whereas 6 (11%) had no or weak (<20% of tumor cells) staining. Among 33 BRAF wild-type colorectal carcinomas, 16 (48%) had no or weak staining, whereas 15 (45%) had heterogeneous staining. In contrast with colorectal carcinoma, Bond and Ventana VE1 IHC in melanoma and PTC were highly concordant with sequencing results. We conclude that VE1 IHC produces suboptimal results in colorectal carcinoma and should not be used to guide patient management.

Solitary fibrous tumor: a clinicopathological study of 110 cases and proposed risk assessment model.

Solitary fibrous tumor represents a spectrum of mesenchymal tumors, encompassing tumors previously termed hemangiopericytoma, which are classified as having intermediate biological potential (rarely metastasizing) in the 2002 World Health Organization classification scheme. Few series have reported on clinicopathological predictors with outcome data and formal statistical analysis in a large series of primary tumors as a single unified entity. Institutional pathology records were reviewed to identify primary solitary fibrous tumor cases, and histological sections and clinical records reviewed for canonical prognostic indicators, including patient age, tumor size, mitotic index, tumor cellularity, nuclear pleomorphism, and tumor necrosis. Patients (n=103) with resected primary solitary fibrous tumor were identified (excluding meningeal tumors). The most common sites of occurrence were abdomen and pleura; these tumors were larger than those occurring in the extremities, head and neck or trunk, but did not demonstrate significant outcome differences. Overall 5- and 10-year metastasis-free rates were 74 and 55%, respectively, while 5- and 10-year disease-specific survival rates were 89 and 73%. Patient age, tumor size, and mitotic index predicted both time to metastasis and disease-specific mortality, while necrosis predicted metastasis only. A risk stratification model based on age, size, and mitotic index clearly delineated patients at high risk for poor outcomes. While small tumors with low mitotic rates are highly unlikely to metastasize, large tumors ≥ 15 cm, which occur in patients ≥ 55 years, with mitotic figures ≥ 4/10 high-power fields require close follow-up and have a high risk of both metastasis and death.