So-called "inflammatory leiomyosarcoma'': a series of 3 cases providing additional insights into a rare entity.

Inflammatory leiomyosarcoma, a rare entity first described in 1995, has been characterized by smooth muscle differentiation, a near-haploid karyotype, and a surprisingly good prognosis. The morphology is similar to that of conventional leiomyosarcoma admixed with a chronic inflammatory infiltrate. Thus far, only 15 cases have been reported in the English language literature. We report the clinical and pathological features of 3 additional cases of inflammatory leiomyosarcoma. Two women (ages 64 and 25, respectively) and 1 man (age 32) presented with a thigh, ovary, and lung mass, respectively. Inflammatory symptoms, such as anorexia, fever, night sweats, abdominal pain, and diarrhea, coincided with the thigh and ovarian primaries. Immunohistochemical studies revealed diffuse positivity for desmin and poor expression for other smooth muscle and skeletal muscle markers (muscle-specific actin [0/3], alpha-smooth muscle actin 1/3 [focal], calponin [1/3], caldesmon [0/3], and myogenin [0/3]). CD68 was diffusely positive in both the histiocytes and spindle cell component in all cases. Ultrastructural evaluation of 1 case (lung primary) lacked definitive smooth muscle differentiation. Cytogenetic analysis in 1 of 2 cases that were karyotyped, identified a near-haploid karyotype, which has been reported in other cases of inflammatory leiomyosarcoma. The other case showed 2 clonal populations of cells with interstitial deletions of the short arm of chromosome 8 and the long arm of chromosome 9, respectively. The case without cytogenetic data was intimately associated with an ovarian mature teratoma. These data also suggest that inflammatory leiomyosarcoma may lack smooth muscle differentiation, characterized by diffuse immunoreactivity for desmin but lack of immunoreactivity for alpha-smooth muscle actin, calponin, and caldesmon. In addition, 2 of the 3 cases developed distant metastases to the lungs, which suggests that these lesions may have a worse prognosis than previously believed.

Heterogeneity of Abnormal RUNX1 Leading to Clinicopathologic Variations in Childhood B-Lymphoblastic Leukemia.

OBJECTIVES: Abnormalities of the RUNX1 gene in childhood B-acute lymphoblastic leukemia (B-ALL) are manifested by ETV6-RUNX1 or RUNX1 amplification. A detailed comparison between the two regarding clinicopathologic features with genetic analysis has not been performed previously. This parallel study assessed how different RUNX1 abnormalities affect the clinicopathology of B-ALL. METHODS: We compared clinicopathologic factors, including age, sex, WBC count, cerebrospinal fluid (CSF) involvement, immunophenotype, and blast proliferation rate between B-ALL with RUNX1 amplification (10 cases) and B-ALL with ETV6-RUNX1 translocation (67 cases) in childhood B-ALL. RESULTS: CD7 was often expressed in RUNX1 amplification but not in ETV6-RUNX1 (44% vs 0%, P = .0001) and appeared to correlate with CSF involvement in the former group (3/4 [75%]). CD13 was often detected in ETV6-RUNX1 with additional RUNX1 gain (38%) with an even higher frequency in double ETV6-RUNX1 translocation (77%), but was not detected in RUNX1 amplification (0%, P < .05). Children with RUNX1 amplification were older and more often CSF positive, while those with ETV6-RUNX1 were younger, more frequently had hyperleukocytosis, and had higher blast proliferation rates. CONCLUSIONS: RUNX1 copy numbers seem to be proportional to the age of B-ALL onset and the frequency of CSF involvement, while RUNX1 amplification vs translocation causes aberrant expression of CD7 and CD13, respectively.