An Update on the Application of Newly Described Immunohistochemical Markers in Soft Tissue Pathology

Abstract

Context During the last 5 to 10 years, significant progress has been made in the molecular characterization of soft tissue tumors, predominantly with the identification of recurrent translocations or amplification of certain genes in different tumor types. Alongside this, translational efforts have identified many novel and diagnostically useful immunohistochemical markers for many of these tumor types. Objective This article reviews a select group of recently described immunohistochemical markers of particular use in the evaluation of mesenchymal neoplasms; the underlying biology of the protein product, practical utility, and limitations of each marker are discussed in detail. Data Sources Literature review, authors' research data, and personal practice experience serve as sources. Conclusions There are many diagnostically useful immunohistochemical markers to help confirm the diagnosis of many different soft tissue tumor types, some of which have reduced the need for additional, and more costly, studies, such as fluorescence in situ hybridization. However, no one marker is 100% specific for a given tumor, and knowledge of potential pitfalls and overlap in patterns of staining among other tumor types is crucial to ensure the appropriate application of these markers in clinical practice.

Low-grade fibromyxoid sarcoma of the external anal sphincter: a case report

“…To confirm the finding, 49 LGFMS cases were evaluated and all exhibited strong and diffuse cytoplasmic staining pattern [3]. However, when applied to suspicious MUC4-negative cases of LGFMS, FUS gene rearrangement should be exploited to guide the diagnosis [9, 18]. …”

Sudden Death Due to Sarcoma: An Unusual Case and Literature Review

“…The adaptation of immunologic methods to histochemical techniques has revolutionized diagnostic pathology, especially for soft-tissue malignancy [27]. Newer immunohistochemical markers facilitate the progress of defining the tumor cell lineage and origin much more accurately than the traditional hematoxylin-eosin method [28][29][30]. Moreover, molecular diagnostic tools, such as fluorescence in situ hybridization (FISH) and DNA sequencing, are now prevalent in diagnosing sarcoma [31,32].…”

Succinate Dehydrogenase Complex: An Updated Review

“…12,22 They show an epithelioid morphology and are often associated with lymphovascular invasion and occasional lymph node metastasis, unlike conventional GISTs. 12,23 Immunohistochemically, most GISTs are positive for C-KIT and DOG1, variably positive for CD34, and rarely positive for smooth muscle actin or desmin. 12 Importantly, immunopositivity to C-KIT and DOG1 will not exclude an underlying SDH deficiency, as most SDH-deficient GISTs are also typically C-KIT and DOG1 positive.…”

“…12 Importantly, immunopositivity to C-KIT and DOG1 will not exclude an underlying SDH deficiency, as most SDH-deficient GISTs are also typically C-KIT and DOG1 positive. 23 SDHB immunoexpression is retained in all GISTs with KIT or PDGFRA mutations, whilst loss of SDHB expression in the neoplastic cells, with positive staining in fibrovascular septa and inflammatory cells, relates to an underlying SDH deficiency (Figure 3, A through C). 23,24 Conventional GISTs typically harbor KIT or PDGFRA mutations; 15% of adult GISTs and greater than 90% in children lack such mutations and are thus so-called wildtype GISTs.…”