Giant cell containing lesions of bone and their differential diagnosis

Giant cell rich lesions encompass a relatively large group of biologically and morphologically diverse bone tumours. They are all related to one another by the presence of numerous multinucleated osteoclast-like giant cells. However, they differ from each other by virtue of their clinical and radiographic characteristics and in many cases, their morphology. In select cases, immunohistochemistry may be necessary to make an accurate diagnosis. The importance of correctly identifying these tumours rests on the differences in their treatment and prognosis.     

Giant cell tumor of bone: Frequent actin immunoreactivity in stromal tumor cells

Although giant cell tumor (GCT) of bone is a well-recognized neoplasm with distinctive clinical and histopathological features, the origin of tumor cells, particularly of mononuclear cells, has not yet been established. An immunohistochemicai study was carried out on 11 cases of GCT of bone to examine the cellular natures of stromal mononuclear cells. In all cases, stromal cells were positive for muscle actin (HHF35) or α-smooth muscle actin, and in eight of 11 cases, positivist was intense and extensive. The cell margin of osteoclast-like giant cells (OGC) was stained positively by muscle actin, In addition to Intense and diffuse positive staining of the cytoplasm for KP1 (CD68), whereas α-smooth muscle acting exhibited a negative reaction on the OGC. In conclusion, the tumor cells with muscle actin and α-smooth muscle actin proclivities are not rare but frequently numerous In the GCT of bone; whereas further observation Is necessary to elucidate whether the stromal cells exhibit myoflbroblastlc cell differentiation exactly.     

Giant cell tumor of soft tissue of the breast: Case report with H3F3A mutation analysis and review of the literature

Giant cell tumors of soft tissue (GCT-ST) arising in the breast are extremely rare. We report a unique case of breast GCT-ST coincident with ductal carcinoma in situ (DCIS), diagnosed with histological, immunohistochemical, and H3F3A (Histone H3.3) mutation analyses. A 59-year-old woman preoperatively diagnosed with DCIS underwent total mastectomy for a cystic mass. Histology revealed a tumor composed of mononuclear cells interspersed with numerous osteoclast-like giant cells, resembling giant cell tumor of bone (GCT-B), with apocrine DCIS in proximity to the tumor. The mononuclear and giant cells were immunoreactive for CD68 and negative for cytokeratins. Granulomatous diseases, carcinomas with giant cells, and giant cell-type sarcomas were excluded by histological and immunophenotypic features. Lack of H3F3A mutation eliminated the possibility of GCT-B metastasizing to the breast. These findings were consistent with GCT-ST of the breast. To our knowledge, this is the ninth reported case of breast GCT-ST, but the first case that accompanied DCIS or involved H3F3A mutation status investigation. For correct diagnosis of this rare tumor, it is important for pathologists to raise the possibility of GCT-ST when encountering giant cell-rich breast lesions and to exclude other differential diagnoses by combining the results of histological, immunohistochemical, and genetic analyses.     

Retiform Sertoli-Leydig cell tumours: clinical,morphological and immunohistochemical findings

AIMS: To determine the morphological and immunohistochemical profile of retiform Sertoli-Leydig cell tumours and to compare the observed profile with that of adult rete ovarii. METHODS AND RESULTS: Nineteen retiform Sertoli-Leydig cell tumours were studied, eight by immunohistochemistry, and five examples of rete ovarii from adult females were also evaluated immunohistochemically. The patients ranged in age from 3 to 74 years with a mean age of 31 years. Four patients were virilized and had an abdominal mass; two were virilized with amenorrhoea and two had amenorrhoea alone. Eight presented with an abdominal mass and one patient was pregnant. Two tumours were incidental findings. Information on stage was available in 16 patients: 14 tumours were stage 1, one was stage 2, and one was stage 3. Fifteen tumours were of intermediate differentiation and four were poorly differentiated. Papillary structures were evident grossly in four cases. Microscopically, all cases had a retiform pattern in addition to varying quantities of sex cord, gonadal stromal and heterologous elements. Heterologous elements were present in 13 cases and consisted of hepatocytes (n = 7), mucinous epithelium (n = 7) and skeletal muscle (n = 2). Immunohistochemical evaluation of eight tumours showed a more intense positivity for keratin in the retiform areas, whereas the gonadal stromal component had a more intense expression of inhibin. Inhibin stains Leydig cells strongly and hepatocytes moderately. Rete ovarii epithelium was positive for keratin and vimentin in the five cases studied, and for inhibin in one case. Follow-up was available on 13 patients. Three tumours behaved in a malignant fashion: one each was stage 1, 2, and 3 at diagnosis. CONCLUSIONS: Immunohistochemistry is useful in distinguishing retiform Sertoli-Leydig cell tumours from other tumours that they may resemble. Inclusion of inhibin is essential in a panel of antibodies to evaluate these tumours. The clinical behaviour of these neoplasms cannot always be predicted from their morphology or clinical stage.     

Giant cell tumor of bone: An immunohistochemical comparative study

Forty-seven cases of giant cell tumor (GCT) of bone were reviewed pathologically to elucidate the origin of spindle-shaped stromal cells or the hlstogenesls of mononuclear histiocytic stromal cells and osteoclast-like giant cells (OCGC). To clarify the histogenesis of OCGC, eight cases of sarcoma associated with OCGC were reviewed for a comparative study. Spindle-shaped stromal cells sometimes produced minute foci of osteoid matrix. Proliferating cell nuclear antigen (PCNA) was observed In spindle-shaped stromal cells and mononuclear histlocytic stromal cells, but not in OCGC. Matrix metalloprotelnase (MMP)-9 was expressed by mononuclear histiocytic stromal cells and OCGC, and its expression was correlated with the lung metastasis rate. In both GCT and sarcomas with OCGC, mononuclear histiocytic stromal cells and OCGC expressed CD68, parathyroid hormone-like protein (PTH-LP), MMP-1 and MMP-9. Immunoreactivity of mononuclear histiocytic stromal cells and OCGC to CD68, PTH-LP, MMP-1 and MMP-9 was similar between GCT and sarcomas with OCGC. These observations may suggest that mononuclear histiocytic stromal cells and OCGC are reactively Induced with several cytokines acting in an autocrine or paracrine fashion and that these cells are closely related with the biologic aggressiveness of GCT.     

Gastrointestinal spindle cell tumours of the dog: histological and immunohistochemical study

To assess the relevance of spindle cell tumours in the canine gastrointestinal (GI) tract and to classify them, a retrospective study was carried out on haematoxylin and eosin-stained sections from formalin-fixed paraffin wax-embedded samples of 105 primary GI tumours. Seventeen out of 105 (16%) GI tumours were mesenchymal, 48% were epithelial and 36% were round cell tumours. Spindle cell tumours were stained by Masson trichrome, Orcein-Van Gieson and labelled immunohistochemically (vimentin, desmin, smooth muscle actin, protein S100, glial fibrillar acid protein, CD117 and MIB-1) and the histological grade, mitotic index, nuclear size and cellular density were also assessed. The 17 gastrointestinal mesenchymal tumours were classified as 10 leiomyomas (10/10 positive for desmin and smooth muscle actin; 6/10 positive for vimentin) 2 leiomyosarcomas (2/2 positive for desmin, smooth muscle actin and vimentin) and 5 gastrointestinal stromal tumours (GISTs) (5/5 positive for CD117 and vimentin; 3/5 positive for smooth muscle actin). Canine GISTs appeared as densely packed spindle cell tumours, with a diffuse, strong, cytoplasmic immunopositivity for c-kit protein (CD117). GISTs, defined as CD117-positive spindle cell or epithelioid or pleomorphic neoplasms that presumably derive from interstitial cells of Cajal, are reported in recent medical studies as the most common mesenchymal tumours of the GI tract. Our data suggest that GISTs represent a significant portion of canine GI spindle cell tumours, which can be definitely distinguished from leiomyosarcomas only by their expression of CD117.     

Cellular heterogeneity in giant cell tumour of bone (osteoclastoma): an immunohistological study of 16 cases

Sixteen cases of giant cell tumour of bone (osteoclastoma) were analysed by immunohistochemical techniques using various monoclonal antibodies specific for macrophages, monocytic and granulocytic cells, T- and B-lymphocytes and other cell types. The multinucleate osteoclastic giant cells failed to react with the majority of antibodies specific for myeloid cells and HLA-DR. In contrast to previous findings, giant cells in some tumours reacted with a rat, but not mouse, antibody to leucocyte common (CD45) antigen. Macrophages were detected in all tumours, though their numbers varied considerably; small numbers of T- and B-lymphocytes were identified in four of 16 cases. The neoplastic, spindle-shaped, stromal cells were largely unreactive with the monoclonal antibodies used in this study, further supporting the view that they are not the precursors of the characteristic giant cells, nor are they of haemopoietic origin.     

Giant cell tumor of bone. A cytologic study of 24 cases

Twenty-three patients with radiologic diagnoses of giant cell tumor of bone underwent fine needle aspiration cytology and needle biopsy for tissue diagnosis before curettage or resection. One patient had two tumors, making a total of 24 cases. The accuracy of the cytologic diagnosis was compared with that of tissue biopsy. Cytologically there were mononucleated and multinucleated cells. The former often occurred in clusters or, less often, were dispersed. They had spindle or plump cell bodies with moderate amounts of cytoplasm and well-defined cytoplasmic membranes. The oval nuclei demonstrated fine, evenly distributed chromatin and small nucleoli. The multinucleated cells were osteoclastlike and were associated with the clusters of mononucleated cells or lying freely. They had a well-demarcated cytoplasm and contained from a few to several dozen monomorphic nuclei. Cytologic diagnosis was made in 20 of 24 cases, and histologic diagnosis was made in 21 of 24. Insufficient diagnostic material for cytology was the reason for failure in 4 cases. This was attributed to faulty technique (2 cases), cystic change (1 case), and massive necrosis (1 case). As other benign and malignant bone tumors may contain benign giant cells, cytologic or histologic findings alone are not diagnostic of giant cell tumor of bone, but should be complemented with the clinicoradiologic findings. Aspiration cytology is as accurate as tissue needle biopsy, may be of high diagnostic value in deeply located lesions not amenable to cutting needle biopsy, and should be done with full knowledge of the clinicoradiographic information.     

A practical approach to immunohistochemical diagnosis of ovarian germ cell tumours and sex cord–stromal tumours

Immunohistochemistry can be useful in the diagnosis of ovarian germ cell tumours and sex cord–stromal tumours. A wide variety of markers are available, including many that are novel. The aim of this review is to provide a practical approach to the selection and interpretation of these markers, emphasizing an understanding of their sensitivity and specificity in the particular differential diagnosis in question. The main markers discussed include those for malignant germ cell differentiation (SALL4 and placental alkaline phosphatase), dysgerminoma (OCT4, CD117, and D2‐40), yolk sac tumour (α‐fetoprotein and glypican‐3), embryonal carcinoma (OCT4, CD30, and SOX2), sex cord–stromal differentiation (calretinin, inhibin, SF‐1, FOXL2) and steroid cell tumours (melan‐A). In addition, the limited role of immunohistochemistry in determining the primary site of origin of an ovarian carcinoid tumour is discussed.     

Ovarian hepatoid yolk sac tumours: morphological, immunohistochemical and ultrastructural features

AIM: The clinicopathological, immunohistochemical and ultrastructural features of two ovarian hepatoid yolk sac tumours (H-YST) from our files are reviewed. METHODS AND RESULTS: Using avidin-biotin-peroxidase complex technique, the immunoprofile of these tumours was compared to that of a classic yolk sac tumour and to that previously reported for hepatocellular carcinomas. The clinicopathological and morphological features of our cases are similar to the seven previously reported ovarian cases. This rare germ cell tumour occurs in young females (mean age = 17.6 years) and presents most commonly with abdominal pain and a large ovarian mass (average size = 140 mm). Histologically, the tumours display a striking resemblance to hepatocellular carcinoma. The absence of an associated typical pattern of yolk sac tumour or other germ cell neoplasm may make it difficult to recognize the germ cell origin of this lesion. Our cases demonstrated positive staining for alpha-fetoprotein and alpha-1-antitrypsin. In addition, there was immunoreactivity with polyclonal carcinoembryonic antigen (CEA) antiserum in a canalicular pattern, focal staining for inhibin, oestrogen and progesterone receptors and absence of immunoreactivity for CK7 that contrasts with the immunophenotype of a usual yolk sac tumour. CONCLUSIONS: Ovarian H-YST and hepatocellular carcinoma share a similar immunoprofile. Ovarian H-YST is a highly aggressive tumour, most patients exhibit recurrence or die of disease within 2 years of diagnosis.     

An H3F3A K27M‐mutation in a sonic hedgehog medulloblastoma

Medulloblastomas are malignant embryonal brain tumours that may harbour mutations in histone‐modifying genes, while mutations in histone genes have not been detected to date. We here describe the first SHH medulloblastoma with H3 K27M mutation. This may have diagnostic implications as H3 K27M mutations are the hallmark of diffuse midline gliomas, H3 K27M mutant, WHO grade IV. Medulloblastomas arise in midline structures and thus must not be mistaken for DMG when using an antibody detecting the H3 K27M mutation.     

An extremely rare case of primary malignancy in giant cell tumor of bone,arising in the right femur and harboring H3F3A mutation

We experienced a case of primary malignancy in giant cell tumor of bone (GCTB), arising in the right femur and harboring H3F3A mutation. A 27-year-old Japanese male without any prior disease history complained of pain in his right hip joint and right lower limb. Radiological images revealed an osteolytic and multicystic lesion existing mainly at the proximal epiphysis of the right femur. Preoperative clinical diagnosis was GCTB, although irregular marginal sclerosis was an atypical radiographic finding for conventional GCTBs. Biopsy sample from the lesion revealed the coexistence of typical GCTB and undifferentiated high-grade round cell sarcoma. Despite of the wide local resection of the tumor with preoperative and postoperative chemotherapy, the patient died of multiple distant metastases of the tumor 9 months after the surgery. Since heterozygous H3F3A c. 103G>T (p. Gly34Trp) mutation was detected not only in the biopsy sample from the primary site with typical GCTB and high-grade sarcoma components but also in the resected material from the metastatic site with only pure high-grade sarcoma component, the tumor was considered originally derived from conventional GCTB and acquire malignant transformation to high-grade sarcoma. Thus, this is an extremely rare case of primary malignancy in GCTB and the first case report of primary malignancy in GCTB proved the presence of H3F3A mutation even in the sarcoma component.     

Detection of H3F3A p.G35W and p.G35R in giant cell tumor of bone by Allele Specific Locked Nucleic Acid quantitative PCR (ASLNAqPCR)

Giant Cell Tumor (GCT) represents about 20% of benign bone tumors, is locally aggressive although malignant transformation is extremely rare, <1% of cases but 2–3% give pulmonary metastasis. Age at onset is between 20 and 40 years with a slight predominance for the female gender.GCT is characterized by specific mutations in H3F3A gene encoding the protein histone 3.3. The study of these mutations is important for the differential diagnosis with giant cell rich sarcomas, chondroblastoma and aneurysmal bone cyst.To identify the most frequent H3F3A mutations we developed a novel allele specific Real Time Polymerase Chain Reaction method, based on Allele Specific Locked Nucleic Acid (ASLNAqPCR) that is here described. Molecular analyses were performed on 20 GCT and 2 osteosarcoma arising on a previous GCT. All cases were verified by Sanger sequencing. We demonstrated that ASLNAqPCR is a quick, sensitive and reliable method to identify mutations of the H3F3A gene, in giant cell tumor of bone, to support diagnosis in morphologically ambiguous cases.     

骨巨细胞瘤TIMP-3启动子甲基化的研究

目的 检测骨巨细胞瘤(GCT)中TIMP—3启动子甲基化及其蛋白表达，探讨该肿瘤组织TIMP—3蛋白表达缺失的原因和TIMP-3启动子甲基化与GCT分级和复发的关系。方法 用免疫组织化学SP法和蛋白免疫印迹检测TIMP—3在GCT组织中的表达，用甲基化特异的PCR(MSP)法检测TIMP—3基因启动子的甲基化状态。结果 TIMP—3主要在单核基质细胞和多核巨细胞的胞质表达，后者的表达具有明显的极向性。17例GCT中有5例(29．4％)TIMP—3蛋白丢失，其中4例的TIMP—3启动子发生异常甲基化，且均为组织学分级为Ⅱ级的病例。结论 GCT的局部骨质破坏，可能与TIMP—3丢失有关；而TIMP—3启动子的异常甲基化，是TIMP—3基因失活和蛋白丢失的重要机制。     

Mixed tumours of the skin: a histopathological, enzyme-histochemical and immunohistochemical study

Twenty-eight cases of mixed tumour of the skin were studied and subclassified into three types: eccrine (1 case), indeterminate (7), and apocrine type (20). The indeterminate type was defined as mixed tumours having tubulo-alveolar patterns with two layers of epithelium, but without apocrine secretion or pilosebaceous differentiation. Enzyme-histochemical studies were performed on four cases (one indeterminate, three apocrine): in the indeterminate type the tubular epithelial cells showed eccrine differentiation while in the apocrine type tubules were found showing the direction of differentiation to be toward the apocrine gland, but tubules with eccrine differentiation were intermingled in all three. Immunohistochemically, no differences were observed between the indeterminate and the apocrine type: hints of eccrine features were observed in both groups. Thus, the indeterminate type could be an eccrine tumour and the apocrine type showed direction of differentiation toward both eccrine and apocrine glands. It is concluded that mixed tumours of the skin are fundamentally eccrine neoplasmas, and that the apocrine features may represent apocrine metaplasia.