Characterization of the myxoid variant of hibernoma.
ABSTRACT Hibernomas are rare benign neoplasms composed of brown adipose tissue. Although they were first mentioned in the literature almost a century ago, relatively few reports have documented their range of pathological features. Multivacuolated fat cells with small, central nuclei are typical features of hibernomas. Based on the nature of the stroma and the appearance of the multivacuolated cells, 4 categories of hibernomas are described: typical, lipoma-like, myxoid, and spindle cell. The myxoid variant is very rare. In this report, we present and characterize the spectrum of morphological features of the myxoid variant of hibernoma by describing the case of a 45-year-old white man who was referred to our hospital for treatment of an ovoid mass in the posterior segment of the right deltoid region. Histopathologic examination of the resected specimen revealed a multilobulated, tan-yellow, variegated tumor with a rubbery consistency that was separated by thick fibrous septa with interspersed collections of foamy histiocytes. The mass was initially diagnosed as schwannoma with degenerative changes, but workup revealed a myxoid variant of hibernoma. This report highlights recent advances that may help confirm the diagnosis and explain the differential diagnosis of this rare tumor. This is one of only a few cases of a myxoid variant of hibernoma reported in the literature.
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ABSTRACT: This paper proposes a novel implementation of the (4:2) redundant adder, which takes advantage of a "don't care" state to introduce a "quiet" state that suppresses glitch propagation in a multiplier's reduction tree. Simulations show that using two 32-bit random words, without Booth encoding, as much as a 10% reduction in driven capacitance can be achieved, which could translate to larger power savings due to the smaller switching activity at the adder's output wires.
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ABSTRACT: Spindle-cell hibernoma is 1 of 4 histologic variants of hibernomas, which are rare lipomatous tumors distinguished from other lipomas by their brown fat component. This article presents a case of a spindle-cell hibernoma that developed in the groin of a 58-year-old man, and is 1 of only 5 known cases of spindle-cell hibernoma published in the scientific literature. Minimal information is available regarding the clinicopathologic characteristics of the 4 hibernoma variants: typical, lipoma-like, myxoid, and spindle-cell. Spindle-cell hibernoma is believed to be the rarest variant, accounting for approximately 2% of hibernomas. The spindle-cell variant predominantly develops in the fourth and fifth decades, with an average age at diagnosis of 42.5 years (range, 28-59 years). It has a male predilection of 4:1. Previously reported only in the posterior neck and scalp, the groin is now added to the sites of spindle-cell hibernoma occurrence. Our patient's tumor demonstrated low-attenuation on computed tomography and contained moderately-attenuating internal septae. Histologically, in addition to the multivacuolated brown fat component common to all hibernomas, spindle-cell hibernoma has a spindle-cell element without vacuolization that is CD34 positive. No prior treatment details are available on this particular variant. Our patient was treated by marginal excision and was disease free through 13 months of follow-up.Orthopedics 01/2010; 33(1):52-5. DOI:10.3928/01477447-20091124-29 · 0.98 Impact Factor
Article: Recurrent lipoma-like hibernoma.[Show abstract] [Hide abstract]
ABSTRACT: This is the fifth report of the rare lipoma-like variant of hibernoma, the 19th case reported, and the first documented as recurring after excision. Our patient was a 56-year-old man whose painful lipoma-like hibernoma (LLH) in the pelvis/buttock was initially treated with marginal excision 15 years earlier. Nine years after treatment, the LLH recurred locally. The recurrence was treated with partial excision and embolization, which alleviated symptoms. The disease was stable 26 months after repeat excision and 202 months after initial treatment. LLH is 1 of the 4 histologic variants of hibernomas, which are rare benign lipomatous tumors distinguished from other lipomas by their brown-fat component. Only minimal information is available regarding the clinicopathologic characteristics of the individual variants. Reviewing the literature, we found that LLH predominantly develops in the fifth and sixth decades, and mean age at diagnosis is 41 years (age range, 2-66 years). LLH has a slight male predilection of 10:9. It most commonly develops in the thigh, with other occurrences reported in the hip, trunk, knee, and calf. The magnetic resonance imaging signal of LLH mirrors fat in all sequences. Presence of internal septations and enhancement with contrast are variable. Histologically, LLH is defined as a hibernoma composed predominantly of univacuolated white-fat cells and only scattered granular or pale hibernoma cells. The literature provides only a few treatment details regarding this variant.American journal of orthopedics (Belle Mead, N.J.) 06/2010; 39(6):E57-60.