Cytogenetic and histologic findings in 17 pulmonary chondroid hamartomas: evidence for a pathogenetic relationship with lipomas and leiomyomas

Endobronchial Hamartoma Presenting as Recurrent Pneumonia and Chronic Cough

Pneumonia is an infection of the lungs that can result from various etiologies, including bronchial obstruction. It is estimated that 5.4% of community-acquired pneumonia occurs as a result of an endobronchial obstruction, classifying them as post-obstructive pneumonia. Pulmonary hamartomas are benign and exceedingly rare tumors. These hamartomas are usually asymptomatic and found incidentally on imaging, however, they can cause patients to develop post-obstructive pneumonia.

We present a 40-year-old female with cough, fatigue, and recurrent right lower lobe pneumonia. Upon workup with bronchoscopy and biopsy, she was subsequently found to have an endobronchial hamartoma resulting in recurrent pneumonia in the same location. We are happy to report that the patient had a resection of the mass, as well as of the affected lung lobe, and has been pneumonia-free for five months. We hope to encourage a greater index of suspicion for endobronchial masses, including rare tumors, when a patient presents with recurrent pneumonia in the same location.

[Hamartochondroma: An unusual cause of endobronchial obstruction in smoking patients]

Endobronchial hamartochondroma is a rare benign tumor which differs from the parenchymal form in its symptomatology and also by its treatment which should be as conservative as possible. The endobronchial location is exceptional. Here we present the cases of two patients with endobronchial hamartochondroma associated with clinical manifestation, chest pain and repeated pulmonary infections, respectively. The diagnosis was made after performing a CT-scan, a PET-SCAN and histological analysis. After discussion in a multidisciplinary staff meeting, conservative treatment was chosen in both cases.

Endobronchial hamartoma; a rare structural cause of chronic cough

Pulmonary hamartomas are rare benign tumors consisting of multiple mesenchymal cell lines like cartilage, bone and fat. We discuss an interesting case of a 53-year-old male patient, who was referred to our clinic for persistent cough. Chest X-ray revealed a left suprahilar density associated with plate like atelectasis, which on chest CT was found to be a densely calcified nodule, causing narrowing of the left upper lobe (LUL) bronchus with calcified bilateral hilar lymph nodes. A bronchoscopy revealed a smooth endobronchial mass with calcification, which was removed. Histopathology revealed pulmonary hamartoma.

The 2015 World Health Organization Classification of Lung Tumors: Impact of Genetic, Clinical and Radiologic Advances Since the 2004 Classification

The 2015 World Health Organization (WHO) Classification of Tumors of the Lung, Pleura, Thymus and Heart has just been published with numerous important changes from the 2004 WHO classification. The most significant changes in this edition involve (1) use of immunohistochemistry throughout the classification, (2) a new emphasis on genetic studies, in particular, integration of molecular testing to help personalize treatment strategies for advanced lung cancer patients, (3) a new classification for small biopsies and cytology similar to that proposed in the 2011 Association for the Study of Lung Cancer/American Thoracic Society/European Respiratory Society classification, (4) a completely different approach to lung adenocarcinoma as proposed by the 2011 Association for the Study of Lung Cancer/American Thoracic Society/European Respiratory Society classification, (5) restricting the diagnosis of large cell carcinoma only to resected tumors that lack any clear morphologic or immunohistochemical differentiation with reclassification of the remaining former large cell carcinoma subtypes into different categories, (6) reclassifying squamous cell carcinomas into keratinizing, nonkeratinizing, and basaloid subtypes with the nonkeratinizing tumors requiring immunohistochemistry proof of squamous differentiation, (7) grouping of neuroendocrine tumors together in one category, (8) adding NUT carcinoma, (9) changing the term sclerosing hemangioma to sclerosing pneumocytoma, (10) changing the name hamartoma to "pulmonary hamartoma," (11) creating a group of PEComatous tumors that include (a) lymphangioleiomyomatosis, (b) PEComa, benign (with clear cell tumor as a variant) and

Neuromuscular and Vascular Hamartoma of the Small Intestine: An Exuberant Reparative Process Secondary to Chronic Inflammation

The term Neuromuscular and Vascular Hamartoma (NMVH) was initially coined by Fernando and McGovern in 1982 in their report of 2 cases. Whether this lesion is truly hamartomatous or represents a "burnt-out" phase of varying chronic pathologies has been debated since that time. Examples of NMVH-like proliferations have been reported in the setting of diaphragm disease, Crohn's disease, radiation, and ischemia. Herein we present the case of a 73-year-old female with partial small bowel obstruction and a past surgical history significant for cholecystectomy and abdominal hysterectomy. A computed tomography scan revealed an ill-defined mass with the same density as muscle extending into the mesentery, worrisome for malignancy and generating the differential of lymphoma versus metastatic disease. Upon laparotomy, a 2.5 cm, constrictive, predominantly mural-based mass was identified. The more proximal bowel was dilated, and there were dense serosal adhesions. Grossly, the transmural lesion had a tan-yellow cobweb-like cut surface and the overlying mucosa was flattened. Histologically, the lesion contained fascicles of smooth muscle, irregularly spaced large nerve bundles, and thick-walled vasculature in a haphazard arrangement within a hypocellular fibroadipose stroma. No stigmata of Crohn's disease were observed, and the uninvolved enteric tissue was unremarkable. The patient's medical history was negative for chronic nonsteroidal anti-inflammatory use and was otherwise unremarkable. This case of an NMVH-like lesion is presented as a reminder of benign mass-forming lesions causing bowel obstruction and suggests that such lesions may develop secondary to a chronic inflammatory process.

Neoplastic and nonneoplastic benign mass lesions of the lung

While most lung neoplasms are malignant, a subset of true neoplasms are benign, the most common of which are pulmonary hamartomas. In addition, a substantial proportion of lung mass lesions are nonneoplastic; granulomas are among the commonly encountered nonneoplastic masses. There is also a group of relatively rare, mainly inflammatory and fibrous tumor-like lesions that are encountered on core biopsy and excisions of lung tissue.

[Giant hamartoma of the lung]

Hamartomas are the most common benign tumors of the lungs and usually present as solitary intraparenchymal lesions a few centimeters in diameter which are detected radiologically as an incidental finding. This article reports on a case of a giant pulmonary hamartochondroma 29 cm in diameter, which impressed preoperatively and intraoperatively as an extrapulmonary neoplasm. The detection of smaller mesenchymal neoplastic lesions in the lungs and pleura is a further special feature of this case.

[Clinical characteristics of resected bronchial hamartoma. Study of seven cases]

INTRODUCTION

Endobronchial hamartoma is a benign tumour derived from peribronchial mesenchymal tissue. It is a form of intrapulmonary hamartoma and can cause irreversible pulmonary destruction due to bronchial obstruction. Early diagnosis and treatment is very important and endoscopic treatment is usually the first choice. In cases in which prolonged bronchial obstruction has produced irreversible lung destruction surgical, resection of the tumour is necessary. The aim of this study is to describe the clinicopathological characteristics of resected endobronchial hamartoma.

PATIENTS AND METHODS

Seven cases of endobronchial hamartoma, diagnosed in our institution between January 1995 and December 2009, were reviewed retrospectively.

RESULTS

The patient population consisted of four males and three females with mean age of 53.7 years (41-68 years). The most frequent clinical presentation was obstructive pneumonia. Endoscopy and imaging showed an endobronchial mass in most cases. Surgical treatment consisted of atypical resection in one case, lobectomy in five cases and pneumonectomy in one case. Tumour size ranged between 0.5 and 3.5 cm. The diagnosis was confirmed in all cases by histological examination. The outcome was favorable in all cases.

CONCLUSION

Endoscopic techniques are effective for the diagnosis and treatment of endobronchial hamartochondroma. Treatment should be prompt to prevent irreversible lung damage due to chronic obstruction and suppuration, in which case, pulmonary resection may be necessary.

C11orf95-MKL2 is the resulting fusion oncogene of t(11;16)(q13;p13) in chondroid lipoma

Chondroid lipoma, a rare benign adipose tissue tumor, may histologically resemble myxoid liposarcoma or extraskeletal myxoid chondrosarcoma, but is genetically distinct. In this study, an identical reciprocal translocation, t(11;16)(q13;p13), was identified in three chondroid lipomas, a finding consistent with previously isolated reports. A fluorescence in situ hybridization (FISH)-based positional cloning strategy using a series of bacterial artificial chromosome (BAC) probe combinations designed to narrow the 16p13 breakpoint revealed MKL2 as the candidate gene. Subsequent 5' RACE studies demonstrated C11orf95 as the MKL2 fusion gene partner. MKL/myocardin-like 2 (MKL2) encodes myocardin-related transcription factor B in a megakaryoblastic leukemia gene family, and C11orf95 (chromosome 11 open reading frame 95) is a hypothetical protein. Sequencing analysis of reverse transcription-polymerse chain reaction (RT-PCR) generated transcripts from all three chondroid lipomas defined the fusion as occurring between exons 5 and 9 of C11orf95 and MKL2, respectively. Dual-color breakpoint spanning probe sets custom-designed for recognition of the translocation event in interphase cells confirmed the anticipated rearrangements of the C11orf95 and MKL2 loci in all cases. The FISH and RT-PCR assays developed in this study can serve as diagnostic adjuncts for the identification of this novel C11orf95-MKL2 fusion oncogene in chondroid lipoma.

Benign Tumors and Tumorlike Conditions of the Lung

Context.—Benign tumors and tumorlike conditions of the lung are encountered in the pathologic evaluation of asymptomatic and symptomatic lung nodules. Since many of these lesions are uncommon, they can be diagnostically challenging.

Objective.—To review the current classification of benign lung tumors, with emphasis on histopathology and useful ancillary studies.

Data Sources.—The current World Health Organization classification system for lung neoplasms and review of relevant publications.

Conclusions.—Despite improved imaging techniques, benign lung nodules are encountered in wedge biopsy and resection specimens. Histopathology, immunohistochemistry, and molecular techniques ensure accurate pathologic diagnosis and have shed light on the histogenesis of these unusual lesions.

Multicystic adenomatoid hamartoma of the pancreas: a hitherto undescribed pancreatic tumor occurring in a 3-year-old boy

This report describes an unusual pancreatic tumor in a 3-year-old boy. He presented with abdominal pain secondary to pancreatitis and was found to have a complex, multicystic lesion within the head of the pancreas. He subsequently underwent a pancreatoduodenectomy. Grossly, the mass was 3 cm, multicystic, and well demarcated. Histologically, there were numerous variably sized, dilated ducts lined by tall columnar mucinous cells surrounded by a stroma that exhibited foci of cellular condensations resembling primitive pancreatic mesenchyme. Acinar and endocrine cells were often seen budding into the ducts forming "ductulo-insular bodies." As a result of its superficial resemblance to Stocker type 2 cystic adenomatoid malformation of the lung, we are proposing the name "multicystic adenomatoid hamartoma" for this lesion.

The genetic heterogeneity of uterine leiomyomata

Research investigating the genetics of UL has already been successful in gathering epidemiologic evidence for heritability, establishing the clonal and mosaic nature of these tumors, correlating genotypic and phenotypic characteristics, defining cytogenetic subgroups, and identifying specific genes involved in tumorigenesis. Although UL are known to be benign tumors, the impact they have on the lives of so many women can only be described as "malignant". For this reason, continuing the quest to ascertain the genes, functions, and mechanisms integral to UL development is absolutely imperative. Genetic tests for personalized medical management of women with fibroids is at the threshold for providing the most appropriate treatments (Fig. 3), and combined with developing less invasive therapies portends a brighter future for a major health problem for women.

Immunoreactivity for Sex Steroid Hormone Receptors in Pulmonary Hamartomas

Sex steroid hormone [ie, estrogen (ER), progesterone (PgR), and androgen (AR)] receptors have been identified previously in normal salivary glands and, more variably, in salivary gland and salivary gland-type tumors. No data are available, however, on their expression in pulmonary hamartoma, a benign biphasic tumor consisting of reactive epithelial cells and neoplastic fibromyxoid stroma, cartilage and fat, which shares some morphologic, immunophenotypic, and genotypic features to pleomorphic adenoma of major salivary glands. Thirty pulmonary hamartomas (15 in male patients and 15 in age-matched female patients), were evaluated for ER, PgR, and AR immunoreactivity, and also for mesenchymal, epithelial, and myoepithelial markers, in the fibromyxoid, epithelial, and chondroid components. ER immunoreactivity was encountered in 90% of hamartomas, PgRs in 90%, and ARs in 53% (P<0.001), but not in normal lung tissues. ARs were confined to males (P<0.001), with a marginal prevalence in the fibromyxoid component (P=0.067). PgRs and ERs were instead present in both sex, with the former being restricted to the fibromyxoid stromal component (P<0.001) and the latter preferentially located in epithelial cells (P=0.107). In most cases, fibromyxoid stroma and spindle cells surrounding the chondroid foci displayed simultaneous immunoreactivity for ERs, PgRs, and ARs, along with immunoreactivity for vimentin, S-100 protein, glial fibrillary acid protein, smooth muscle actin, and calponin but lack of staining for cytokeratins. This profile is consistent with an incomplete myoepithelial differentiation of the receptor-expressing mesenchymal cells. In conclusion, sex steroid hormone receptor expression is a nonrandom event in pulmonary hamartoma, and may be related to the development and growth of this tumor.

A clonal dic(16;21)(p13.1;p11.2)del(16)(q11.1), with gains of several chromosomes and monosomy 21, in a case of splenic hamartoma: evidence for its neoplastic, not hamartomatous, origin

Cytogenetic examination of a case of splenic hamartoma led to the discovery of a clonal population with the karyotype 47 approximately 58,XX,+X,+4,+5,+5,+6,+10,+12,+14,der(16)dic(16;21)(p13.3;p11.2), dic(16;21)del(16)(q11.1),+17,+19,+20,-21. This finding is indicative of a neoplastic, not hamartomatous, origin for this lesion.

Inversion of chromosome 12 and lineage promiscuity in hematologic malignancies

Rearrangements of the short arm of chromosome 12 are among the most common aberrations found in hematologic malignancies, including myelodysplastic syndromes, acute myelocytic leukemias, acute lymphoblastic leukemias, and non-Hodgkin lymphomas. We report on a group of 46 patients with a variety of myelocytic and lymphoid malignancies, all with an inversion of chromosome 12. Both pericentric and paracentric inversions occurred. The identified hotspots for breakage were p13 and q24. These correspond to gene-rich areas of known chromosome instability. The inv(12) is difficult to detect and may be misinterpreted as a partial deletion by routine cytogenetics. Fluorescence in situ hybridization studies revised the G-banding interpretations of a deleted 12p in some cases to an inversion. The inv(12) may occur as the sole abnormality in both myelocytic and lymphoid malignancies, suggesting lineage promiscuity as seen with MLL and ETV6 gene disruptions. The majority of patients with the inv(12) had complex karyotypic changes that predicted a poor prognosis. Of the 24 patients with known clinical follow-up, many were refractory to chemotherapy and overall survival was short.

Recombinations of chromosomal bands 10q24, 12q14-q15, and 14q24 in two cases of pulmonary chondroid hamartoma studied by fluorescence in situ hybridization

Pulmonary chondroid hamartomas (PCH) are benign mesenchymal tumors consisting of at least two cytogenetic subgroups. These subgroups are defined by chromosomal alterations at either 12q14-q15 or 6p21. Cytogenetic analysis of short-term cultures from two PCHs revealed two different rearrangements with 12q14 -q15. One of these had a unique translocation t(12;14)(q14-15;q24) with presence of two normal chromosomes 12 and a der(14), but missing the der(12). The other showed a complex rearrangement between chromosomes 10 and 12 with two different derivatives. Our data have been confirmed with fluorescence in situ hybridization analysis. These cases represent variant forms of the standard translocations.

Epithelial and soft tissue tumors of the tracheobronchial tree

This article provides a broad overview of tumors that can involve the tracheobronchial tree. For the most part, the clinical, radiographic, and endoscopic presentation of these rare tumors does not differ significantly from the more common tumors of the lung. Appropriate classification of many tracheobronchial tumors ultimately requires complete sampling and a thorough microscopic evaluation. The introduction of ancillary diagnostic techniques such as immunohistochemistry and molecular analysis will continue to refine tumor classification.

Inv(12)(q15q24): a nonrandom change associated with myelodysplasia?

A patient with refractory anemia and a paracentric inversion of chromosome 12, inv(12)(q15q24), is described. This is the second reported case with this chromosome anomaly, suggesting that this rearrangement is a rare but nonrandom change associated with myelodysplastic syndromes.

An immunohistochemical study of the mesenchymal and epithelial components of pulmonary chondromatous hamartomas

Twenty-five cases of solitary pulmonary chondromatous hamartomas (PCH) were examined by immunohistochemistry to evaluate the mesenchymal and epithelial components. PCH composed of predominantly mature cartilage were designated as C type, those predominantly composed of fibromyxoid tissue as FM type, and those predominantly composed of adipose tissue as A type. FM type PCH revealed various amounts of cartilage in various developmental stages, adipose tissue and fibromyxoid tissue, compared with a uniform pattern of cartilage tissue in C type. The cells of transitional form between spindle cells, stellate cells and chondrocytes were present in FM type. Epithelial components in PCH were bronchial, bronchiolar and cuboidal cells, mostly at the periphery of PCH. S-100 protein consistently stained chondrocytes, stellate and spindle cells in the fibromyxoid tissue of solitary PCH. Fibroblast growth factor was immunolocalized to chondrocytes, spindle and stellate cells in the fibromyxoid tissue. The collagen type was associated with differentiation from primitive mesenchymal cells to chondrocytes (i. e. type I and III collagen appeared in fibromyxoid matrix and type II collagen in the cartilaginous matrix). Fibronectin coordinately appeared with type I and III collagens. The proliferating cell nuclear antigen labeling index of epithelial cells was comparable to those of neoplastic mesenchymal cells, but it was not significantly different between C type and FM type PCH. The primitive mesenchymal cells in the bronchial walls of the control premature neonates were also observed. This immunohistochemical study showed that the progenitor mesenchymal cells in the bronchial and bronchiolar walls may differentiate along chondrocytes, lipocytes, and smooth muscle cells in PCH and that epithelial proliferation is reactive and closely associated with neoplastic proliferation of the mesenchymal component.

A new observation of the Carney's triad with long follow-Up period and additional tumors

The etiology of the Carney's triad (gastrointestinal stromal tumors, pulmonary chondromas, and paragangliomas) is unknown, and only 57 cases have been reported since its identification in 1977. We report the clinical course of a female with the complete triad and some additional tumors. Bilateral vagal paragangliomas were treated surgically and with radiotherapy between the ages of 24 and 26 years. Subsequently she underwent surgery for a gastric leiomyosarcoma (27 years), a pleomorphic adenoma of the parotid gland (49 years) and a multifocal breast cancer with axillary spread (50 years). A calcified lesion was also noticed in the left lung, the radiologic diagnosis of which was consistent with chondroma. A mediastinal paraganglioma, detected at 56 years on a control X-ray of the chest, was partially excised at 63 years. At the last control, performed at 66 years, the patient was alive with residual cervical and mediastinal paraganglioma. Her younger brother was affected by Hirschsprung's disease and died at 54 years of rectal cancer. Her daughter is 33 and has been suffering since birth with severe constipation. In conclusion, this is one of the longest followed-up patients with Carney's triad. Her case illustrates the need for early recognition of the setting in order to detect the component tumors at a stage when surgery may be curative, and careful and life-long follow-up, both because the multicentricity of the classic components tends to manifest metachronously and because of the tendency to develop other tumors, some of which may be malignant. Furthermore, the presence of Hirschsprung's disease in the patient's family, coupled with the alleged common origin of two component lesions from derivatives of the neural crest, open new avenues for the understanding of this disorder.

Inflammatory myofibroblastic tumor with HMGIC rearrangement

Inflammatory pseudotumors or inflammatory myofibroblastic tumors (IMT) are lesions of extreme heterogeneity showing a highly variable mixture of bland-looking spindle cells, inflammatory cells, and collagen fibers. We describe our results of molecular cytogenetic and rapid amplification of cDNA ends (RACE-PCR) studies on an IMT characterized by a translocation involving 12q15. Chromosomal aberrations involving this region are very frequent among other benign tumors, such as lipomas, uterine leiomyomas, or pulmonary chondroid hamartomas. Recently, we have shown that, by these structural chromosomal aberrations, the HMGIC gene is affected. Fluorescence in situ hybridization (FISH) analysis and 3' RACE-PCR on cells of the present case of an inflammatory myofibroblastic tumor indicated an intragenic rearrangement of HMGIC, resulting in an aberrant transcript of that gene. Clonal cytogenetic aberrations have been described in very few cases of IMT. The results presented herein indicate that this case of IMT represents a true benign mesenchymal neoplasm associated with, or due to, a rearrangement of HMGIC.

Pleomorphic adenomas of the salivary glands: absence of HMGIY rearrangements

Rearrangements of chromosome region 12q14-15 affecting the HMGIC gene are a frequent finding in benign solid tumors. Another non-random chromosomal alteration observed in subgroups of several of the tumor entities with 12q14-15 changes are rearrangements of 6p21 resulting in alterations of the HMGIY gene, which have so far not been documented in pleomorphic adenomas of the salivary glands. In our series of 335 pleomorphic adenomas, karyotypic changes affecting chromosomal region 6p21-23 were observed in five tumors all showing either a simple or complex t(6;8)(p21-p23;q12). Molecular cytogenetic studies of two of these tumors revealed that the 6p-breakpoint of this translocation maps distal to HMGIY, not affecting the gene or its closer vicinity. The results strongly suggest that pleomorphic adenomas are the only exception to the rule that entities of benign tumors with HMGIC rearrangements also have subtypes with HMGIY rearrangements. The difference from the other tumors is discussed in terms of tissue specificity of both HMG protein genes.

Fibrous hamartoma of infancy: current review

This review examines 197 cases of fibrous hamartoma of infancy (FHI) described in the literature and provides a detailed clinicopathologic analysis of what is known to date of this peculiar lesion of the subcutis and lower dermis. The vast majority of these cases occurred within the first year of life (91%). Twenty-three percent were congenital. There was a predilection for boys with a male/female ratio of 2.4. Males and females had similar anatomic distribution with the most common locations being the axillary region, upper arm, upper trunk, inguinal region, and external genital area. Most cases presented as solitary masses, but four cases of multiple separate synchronous lesions have been reported. Most lesions presented as a painless nodule, sometimes with rapid growth. A few cases had overlying skin changes, including alteration in pigmentation, eccrine gland hyperplasia, and increased hair. No lesions were reported to have familial or syndromic association, or to occur in combination with other hamartomas. Spontaneous regression has not been reported. The treatment of choice is local excision. Even with incomplete excision, FHI has a low recurrence rate. Criteria for histologic diagnosis include the presence of well-defined bundles of dense, uniform, fibrous connective tissue projecting into fat, primitive mesenchyme arranged in nests, concentric whorls or bands, and mature adipose tissue intimately admixed with the other components. Flow-cytometric and conventional cytogenetic studies have not been reported; these may clarify any relationship to other fibroblastic/myofibroblastic proliferations in children, resulting in better classification and terminology of this unique lesion.

Localization and expression of the human estrogen receptor beta gene in uterine leiomyomata

Estrogens have an important function in the natural history of uterine leiomyomata. The human estrogen receptor beta gene (ESR2) has been identified recently and mapped to 14q22-24, a region frequently rearranged in uterine leiomyomata and other benign tumors, including pulmonary chondroid hamartomas and endometrial polyps. Using fluorescence in situ hybridization and radiation hybrid mapping, we map ESR2 within 14q23-24.1, to a region approximately 2 Mb centromeric to the t(12;14) breakpoint in uterine leiomyomata, between markers D14S63 and WI-7536. Two YAC clones, 948B6 and 741H4, contain ESR2. Using RT-PCR, we show that ESR2 is expressed in uterine leiomyomata and pulmonary chondroid hamartomas as well as in normal myometrium. Lack of a direct relationship between rearrangement of 14q23-24 and ESR2 expression suggests that ESR2 is not involved with HMGIC or HMGIY in t(12;14) or t(6;14). However, because of its relatively close physical distance from the characteristic site of rearrangements in 14q23-24, a role for ESR2 in the pathobiology of these tumors warrants future consideration.

Genomic and functional map of the chromosome 14 t(12;14) breakpoint cluster region in uterine leiomyoma

A translocation involving chromosomes 12 and 14 [t(12;14)(q15;24.1)] is commonly seen in benign smooth muscle tumor as uterine leiomyoma (UL). A contig of P1-derived artificial chromosome and bacterial artificial chromosome clones on chromosome 14, encompassing a t(12;14) breakpoint cluster region (BCR) in UL, was generated principally using the recently developed HAPPY map of chromosome 14 as a framework (P. H. Dear et al., 1998, Genomics 48: 232-241). Three UL t(12;14) breakpoints have been localized within this contig, showing that a BCR of at least 400 kb exists on chromosome 14. Other studies of tumors with t(12;14) rearrangements similarly show breakpoints within a 475-kb multiple aberration region on chromosome 12. Thus t(12;14) is an example of a translocation in which the breakpoints are located within a BCR on both chromosome 12 and chromosome 14, justifying the identification of expressed sequences that are altered in these BCR regions. A total of four expressed sequences were identified in the BCR on chromosome 14. Two of these were novel cDNAs (D14S1460E and D14S1461E). The chromosome 14 cDNAs were expressed in multiple adult tissues. The identification of a large breakpoint cluster region on chromosome 14 suggests that translocations in this region mediate their effects at a distance and also that elements that predispose this region to recurrent chromosomal translocation may be widely distributed.

The t(3;12)(q27;q14-q15) with underlying HMGIC-LPP fusion is not determining an adipocytic phenotype

The HMGIC gene, located in chromosome band 12q15, is rearranged in many different benign human tumors, often resulting in its fusion to ectopic sequences from other genes. The t(3;12)(q27;q14-q15) fuses HMGIC with the LPP gene and has so far been described exclusively in lipomas. Thus, it can be hypothesized that this particular gene fusion determines the adipocytic differentiation. We studied five pulmonary chondroid hamartomas all showing a t(3;12)(q27;q14-q15) that apparently was identical to the one observed in lipomas. By fluorescence in situ hybridization we found that both HMGIC and LPP are disrupted by this translocation. By RT-PCR the existence of a HMGIC/LPP fusion gene was confirmed. These results show that the fusion is not specific for lipomas. We favor the hypothesis that it is an ectopic sequence fused to HMGIC that is responsible for a cell shift to an embryogenic stage. Following this hypothesis the phenotype of the tumor may be induced by extracellular signal transduction.

Endobronchial lipomatous hamartoma: a rare cause of bronchial occlusion

A 74-year-old man presented with shortness of breath and vague chest pain. A chest roentgenogram showed subtotal atelectasis of the upper lobe of the left lung and a CT scan revealed an occlusion of the bronchus of the upper lobe of the left lung by an intraluminal tumor. A well-circumscribed yellow tumor obstructing the bronchus of the upper lobe of the left lung was seen by fiberoptic bronchoscopy. Biopsies revealed mature fat tissue and small areas with bone consistent with the diagnosis of an endobronchial predominantly lipomatous hamartoma.

Translocation breakpoints upstream of the HMGIC gene in uterine leiomyomata suggest dysregulation of this gene by a mechanism different from that in lipomas

Uterine leiomyomata are the most common pelvic tumors in women and are the indication for more than 200,000 hysterectomies annually in the United States. Rearrangement of chromosome 12 in bands q14-q15 is characteristic of uterine leiomyomata and other benign mesenchymal tumors, and we identified a yeast artificial chromosome (YAC) spanning chromosome 12 translocation breakpoints in a uterine leiomyoma, a pulmonary chondroid hamartoma, and a lipoma. Recently, we demonstrated that HMGIC, which is an architectural factor mapping within the YAC, is disrupted in lipomas, resulting in novel fusion transcripts. Here, we report on the localization of translocation breakpoints in seven uterine leiomyomata from 10 to > 100 kb upstream of HMGIC by use of fluorescence in situ hybridization. Our findings suggest a different pathobiologic mechanism in uterine leiomyomata from that in lipomas. HMGIC is the first gene identified in chromosomal rearrangements in uterine leiomyomata and has important implications for an understanding of benign mesenchymal proliferation and differentiation.

Chromosome rearrangements in synovial chondromatous lesions

Short-term cultures from one synovial chondroma and three cases of synovial chondromatosis, a lesion for which no previous karyotypic information exists, were cytogenetically analysed. Whereas the chondroma displayed the relatively simple karyotype 46,XY,add(12)(q13),der(17)t(12;17)(q13;q21), more complex changes were found in the three cases of chondromatosis: case 1, 47,XY,der(1)inv(1)(p13q25)del (1)(q25q32), t(1;12)(q25;q13), + 5,der(12)add(12)(p11)t(1;12)(p22;q13); case 2, 47,XY,add(10)(q26), + 20/46 idem,-6/46,XY,t(2;4)(q33;q21), add(21)(p11); and case 3, 44,XY,add(1)(p36), del(1)(p13p22),add(6)(p25), del(7) (q22q32),del(10)(q21),add(11)(q13),-17,-18. The cytogenetic findings strongly suggest that synovial chondro-matosis is a clonal proliferation. Apart from a near-diploid chromosome number, the only recurrent cytogenetic features among the four cases were loss of band 10q26 and rearrangements of 1p13 and 12q13, found in two cases each. While chromosome bands 1p13 and 10q26 have not been reported to be involved in other types of benign chondromatous lesions, the 12q13-15 segment is recurrently rearranged in a variety of chondromatous tumours, e.g. pulmonary chondroid hamartomas. The present finding of translocations affecting band 12q13 in two of the cases emphasises that, irrespective of the anatomical localisation of the tumours, rearrangements of genes in 12q13-15 are important in the development of a large subset of benign and malignant cartilage-forming tumours.

A nonbalanced translocation (10;16) demonstrated by FISH analysis in a case of alveolar adenoma of the lung

Short-term cultures from an alveolar adenoma of the lung were cytogenetically examined. Of the 54 metaphases studied, 44 were characterized by an apparently normal karyotype and 10 showed a pseudodiploid karyotype: 46,XX,add(16)(q24). Fluorescence in situ hybridization studies permitted identification of the add(16)(q24) as a der(16)t(10;16)(q23;q24). This is the first report of a chromosomal aberration in an alveolar adenoma of the lung.

Transcriptional activation of HMGI-C in three pulmonary hamartomas each with a der(14)t(12;14) as the sole cytogenetic abnormality

Aberrations involving the chromosomal region 12q14-15 are non-random cytogenetic abnormalities in many benign tumors, e.g. pulmonary chondroid hamartomas (PCH). Recently, we identified rearrangements of the HMGI-C gene within the third or fourth intron as the molecular mechanism underlying most of these chromosomal aberrations. Herein we report our FISH and RACE studies on three PCHs each showing a rare variant type of the translocation t(12;14)(q14-15;q24) with presence of two normal chromosomes 12 and a der(14) but missing the der(12). The results revealed that in all three cases the breakpoint is located 5' to HMGI-C, suggesting that besides intragenic rearrangements also transcriptional activation of the gene can initiate tumor growth.

Variant translocation t(6;10)(p21;q22) in pulmonary chondroid hamartoma

Banding cytogenetics and fluorescence in situ hybridization analysis of a pulmonary chondroid hamartoma (PHC) showed the presence of a t(6;10)(p21;q22). A cytogenetically identical translocation has previously been found in another case of PHC, suggesting that it could represent a variant form of the standard t(6;14)(p21;q24).

t(4;19)(q35;q13.1): a recurrent change in primitive mesenchymal tumors?

We report an apparently balanced t(4;19)(q35;q13.1) as the sole cytogenetic change in a highly malignant extraskeletal sarcoma in a 12-year-old-boy. Tumor cells were negative for all immunocytochemical markers except vimentin and neuron-specific enolase. Electron microscopy indicated chondroblastic differentiation. The tumor was categorized as a malignant sarcoma with differentiation toward extraskeletal mesenchymal chondrosarcoma. Reports of a similar translocation in an embryonal rhabdomyosarcoma (RMS) and in a dedifferentiated sarcoma with both rhabdomyosarcomatous and osteosarcomatous elements suggest that this translocation can arise in a primitive mesenchymal stem cell that can differentiate along at least these three pathways.

Identification of a YAC spanning the translocation breakpoints in uterine leiomyomata, pulmonary chondroid hamartoma, and lipoma: physical mapping of the 12q14-q15 breakpoint region in uterine leiomyomata

Uterine leiomyomata are the most common tumors in women and can cause abnormal uterine bleeding, pelvic pain, and infertility. Approximately 200,000 hysterectomies are performed annually in the U.S. to relieve patients of the medical sequelae of these benign neoplasms. Our efforts have focused on cloning the t(12;14)(q14-q15;q23-q24) breakpoint in uterine leiomyoma to further our understanding of the biology of these tumors. Thirty-nine YACs and six cosmids mapping to 12q14-q15 have been mapped by fluorescence in situ hybridization to tumor metaphase chromosomes containing a t(12;14). One YAC spanned the translocation breakpoint and was mapped to tumor metaphases from a pulmonary chondroid hamartoma containing a t(12;14)(q14-q15;q23-q24) and a lipoma containing a t(12;15)(q15;q24); this YAC also spanned the breakpoint in these two tumors, suggesting that the same gene on chromosome 12 may be involved in the pathobiology of these distinct benign neoplasms.