A massive open cluster hiding in full sight

Obscuration and confusion conspire to limit our knowledge of the inner Milky Way. Even at moderate distances, the identification of stellar systems becomes compounded by the extremely high density of background sources. Here we provide a very revealing example of these complications by unveiling a large, massive, young cluster in the Sagittarius arm that has escaped detection until now despite containing more than 30 stars brighter than G = 13. By combining Gaia DR2 astrometry, Gaia and 2MASS photometry and optical spectroscopy, we find that the new cluster, which we name Valparaiso 1, located at ∼2.3 kpc, is about 75 Ma old and includes a large complement of evolved stars, among which we highlight the 4 d classical Cepheid CM Sct and an M-type giant that probably represents the first detection of an AGB star in a Galactic young open cluster. Although strong differential reddening renders accurate parameter determination unfeasible with the current dataset, direct comparison to clusters of similar age suggests that Valparaiso 1 was born as one of the most massive clusters in the Solar Neighbourhood, with an initial mass close to 104 M⊙.

Fibrous Dysplasia at Unusual Anatomic Sites: A Series of 86 Cases With Emphasis on Histologic Patterns

Aims. Fibrous dysplasia (FD) is a benign fibro-osseous neoplasm that most commonly arises in the ribs, femur, and craniofacial bones. We analyzed features of FD arising in the spine/short tubular/small bones of the hands/feet (STSBHF), specifically assessing for pattern of bone formation (conventional, complex/anastomosing, psammomatoid/cementum like), myxoid change, and presence of osteoclast-type giant cells. Materials and methods. A total of 1958 cases of FD were reviewed, of which 131 arose in the spine/STSBHF representing 2.5% of institutional and 10% of consultation cases, respectively. Eighty-six cases had material available for review. Anatomic sites included vertebrae ( n = 58, 67%), short tubular bones ( n = 20, 23%), and small bones of the hands/feet ( n = 8, 9%). The most common morphologic pattern of bone identified was conventional ( n = 77, 90%), followed by complex/anastomosing ( n = 22, 26%) and psammomatoid/cementum like ( n = 22, 26%). Eighteen cases (21%) had matrix-poor areas. Hypercellular areas were identified in 6 cases, 2 cases of which showed matrix-poor areas. Osteoclast-type giant cells were noted in 9 cases and myxoid change was present in 3 cases. Radiologic imaging studies available for 41 cases nearly all demonstrated features typical of FD, but the diagnosis was not predicted due to the unexpected location. Conclusions. FD arising in the spine/STSBHF is rare and frequently results in expert consultation. A significant number of cases exhibited less commonly recognized patterns of bone formation, and stromal changes including osteoclast-type giant cells, and matrix poor areas. Furthermore, imaging features in the STSBHF are often less specific. Awareness of the morphologic spectrum at these locations coupled with radiologic correlation should aid in accurate classification.

Recurrent novel HMGA2-NCOR2 fusions characterize a subset of keratin-positive giant cell-rich soft tissue tumors

Giant cell tumors of soft tissue (GCT-ST) are rare low-grade neoplasms that were at one time thought to represent the soft tissue counterparts of GCT of bone (GCT-B) but are now known to lack the H3F3 mutations characteristic of osseous GCT. We present six distinctive giant cell-rich soft tissue neoplasms that expressed keratins and carried a recurrent HMGA2-NCOR2 gene fusion. Patients were five females and one male aged 14–60 years (median, 29). All presented with superficial (subcutaneous) masses that were removed by conservative marginal (3) or wide (2) local excision. The tumors originated in the upper extremity (2), lower extremity (2), head/neck (1), and trunk (1). Five patients with follow-up (median, 21 months; range, 14–168) remained disease-free. Grossly, all tumors were well-demarcated but not encapsulated with variable lobulation. Histologically, they were composed of bland plump epithelioid or ovoid to spindled mononuclear cells admixed with evenly distributed multinucleated osteoclast-type giant cells. Foci of stromal hemorrhage and hemosiderin were seen in all cases. The mitotic activity ranged from 2 to 14/10 high power fields (median: 10). Foci of necrosis and vascular invasion were seen in one case each. The mononuclear cells were immunoreactive with the AE1/AE3 keratin cocktail and less frequently/less diffusely for K7 and K19 but lacked expression of other lineage-associated markers. RNA-based next-generation sequencing revealed an HMGA2-NCOR2 fusion in all tumors. None of the keratin-negative conventional GCT-ST showed the HMGA2-NCOR2 fusion (0/7). Metaplastic bone (4/9) and SATB2 expression (3/4) were frequent in keratin-negative conventional GCT-ST but were lacking in keratin-positive HMGA2-NCOR2 fusion-positive tumors. The distinctive immunophenotype and genotype of these tumors strongly suggest that they represent a discrete entity, differing from conventional GCT-ST and other osteoclast-rich morphologic mimics. Their natural history appears favorable, although a study of additional cases and longer follow-up are warranted.

Posterior Pharyngeal Wall Tuberculosis—A Forgotten Entity Mimicking Malignancy

Background: Tuberculosis (TB) of posterior pharyngeal wall (PPW), either primary or secondary, is extremely rare and can mimic malignancy in elderly patients. Case Report: A 36-year-old female patient presented with complains of nonhealing ulcer at the back of her throat for 4 months. On examination, there was an ulceroproliferative growth covered with slough over PPW. Positron emission tomography scan showed uptake in PPW. There was no uptake in any other part of body. A biopsy from PPW lesion showed epithelioid cell granulomas with Langhans type giant cells. Auramine-rhodamine staining showed few beaded bacilli consistent with TB. Conclusion: Tuberculosis of PPW is an extremely uncommon entity and can mimic malignancy. It should be kept as one of the differential diagnosis as it can be cured solely by giving anti-tubercular therapy.

Recurrence-free management of type 2 variant of giant cell tumour of extensor tendon sheath of thumb

A 30-year-old woman presented with swelling in her right thumb of 3-month duration which was slow-growing in nature without a history of trauma. On examination, firm non-tender swelling with ill-defined border over the dorsomedial aspect of the first metacarpal was noted. The swelling was mobile only in the vertical plane with restricted adduction and abduction. Plain X-ray revealed mild erosion of the first metacarpal head. Diagnostic ultrasound confirmed the lesion to arise from the extensor tendon sheath of diffuse type without any bony involvement. A wide local excision biopsy of the swelling was planned. Intraoperatively, a 3×2 cm greyish-white mass, bony hard in consistency with lobulated surface was found arising from the tendon sheath of the extensor tendon of the thumb; it was completely excised with a wide margin. Histopathological examination revealed polyhedral cells admixed with osteoclastic type giant cells. Biopsy from the first metatarsal was normal. The patient is on follow-up for the last 5 years with no evidence of recurrence.

Exogenous Lipoid Pneumonia Presenting as an Enlarging Lung Nodule in a Patient with a Long-standing Usage of Petroleum Jelly

Introduction/Objective Lipoid pneumonia is an uncommon inflammatory lung lesion resulting from the aspiration of endogenous or exogenous oily substances. It has no age or sex preponderance, and its mode of presentation is non- specific. Radiologic imaging findings may mimic that of a malignant lung lesion. Methods We report a case of a 69-year-old female with a history of chronic obstructive pulmonary disease, rheumatoid arthritis and a 30-pack year smoking. She was being followed for an enlarging PET positive spiculated left upper lung nodule. She underwent a CT-guided core biopsy of the lung nodule. Results Biopsy showed histiocytes and multinucleated giant cells with lipid vacuoles and associated marked fibrosis. Review of a percutaneous lung biopsy performed two years prior showed a chronic inflammatory process with associated fibrosis in the presence of nonpolarizable vacuoles, many of which were intracytoplasmic within multinucleate foreign body type giant cells. A re-assessment of the patient with further history taking revealed a longstanding practice of nighttime application of petroleum jelly to nostrils and lips. Together, these findings are consistent with an exogenous lipoid pneumonia. Conclusion Lipoid pneumonia although an entity with limited literature description, should be considered in patients presenting with enlarging lung nodules. Early diagnosis of this lesion ensures appropriate treatment and prevents unnecessary invasive procedures.

Is HR 6819 a triple system containing a black hole?

Context. HR 6819 was recently proposed to be a triple system consisting of an inner B-type giant plus black hole (BH) binary with an orbital period of 40 d and an outer Be tertiary. This interpretation is mainly based on two inferences: that the emission attributed to the outer Be star is stationary and that the inner star, which is used as mass calibrator for the BH, is a B-type giant. Aims. We re-investigate the properties of HR 6819 to search for a possibly simpler alternative explanation for HR 6819, which does not invoke the presence of a triple system with a BH in the inner binary. Methods. Based on an orbital analysis, the disentangling of the spectra of the two visible components and the atmosphere analysis of the disentangled spectra, we investigate the configuration of the system and the nature of its components. Results. Disentangling implies that the Be component is not a static tertiary, but rather a component of the binary in the 40 d orbit. The inferred radial velocity amplitudes of K1 = 60.4 ± 1.0 km s−1 for the B-type primary and K2 = 4.0 ± 0.8 km s−1 for the Be-type secondary imply an extreme mass ratio of M2/M1 = 15 ± 3. We find that the B-type primary, which we estimate to contribute about 45% to the optical flux, has an effective temperature of Teff = 16 ± 1 kK and a surface gravity of log g = 2.8 ± 0.2 [cgs], while the Be secondary, which contributes about 55% to the optical flux, has Teff = 20 ± 2 kK and log g = 4.0 ± 0.3 [cgs]. We infer spectroscopic masses of 0.4−0.1+0.3and 6−3+5 for the primary and secondary which agree well with the dynamical masses for an inclination of i = 32°. This indicates that the primary might be a stripped star rather than a B-type giant. Evolutionary modelling suggests that a possible progenitor system would be a tight (Pi ≈ 2 d) B+B binary system that experienced conservative mass transfer. While the observed nitrogen enrichment of the primary conforms with the predictions of the evolutionary models, we find no indications for the predicted He enrichment. Conclusions. We suggest that HR 6819 is a binary system consisting of a stripped B-type primary and a rapidly-rotating Be star that formed from a previous mass-transfer event. In the framework of this interpretation, HR 6819 does not contain a BH. Interferometry can distinguish between these two scenarios by providing an independent measurement of the separation between the visible components.

Superflares on the late-type giant KIC 2852961

Context. The most powerful superflares reaching 1039 erg bolometric energy are from giant stars. The mechanism behind flaring is thought to be the magnetic reconnection, which is closely related to magnetic activity (including starspots). However, it is poorly understood how the underlying magnetic dynamo works and how the flare activity is related to the stellar properties that eventually control the dynamo action. Aims. We analyze the flaring activity of KIC 2852961, a late-type giant star, in order to understand how its flare statistics are related to those of other stars with flares and superflares, and to understand the role of the observed stellar properties in generating flares. Methods. We searched for flares in the full Kepler dataset of KIC 2852961 using an automated technique together with visual inspection. We cross-matched the flare-like events detected by the two different approaches and set a final list of 59 verified flares during the observing term. We calculated flare energies for the sample and performed a statistical analysis. Results. The stellar properties of KIC 2852961 are revised and a more consistent set of parameters are proposed. The cumulative flare energy distribution can be characterized by a broken power law; that is to say, on the log-log representation the distribution function is fitted by two linear functions with different slopes, depending on the energy range fitted. We find that the total flare energy integrated over a few rotation periods correlates with the average amplitude of the rotational modulation due to starspots. Conclusions. Flares and superflares seem to be the result of the same physical mechanism at different energy levels, also implying that late-type stars in the main sequence and flaring giant stars have the same underlying physical process for emitting flares. There might be a scaling effect behind the generation of flares and superflares in the sense that the higher the magnetic activity, the higher the overall magnetic energy released by flares and/or superflares.