Fibrous Dysplasia Masquerading as Sternal Malignancy: A Rare and Challenging Presentation

This case report presents a rare and challenging manifestation of polyostotic fibrous dysplasia (FD), a skeletal developmental anomaly characterized by the proliferation of fibrous connective tissue intermingled with irregular bony trabeculae. While monostotic FD is more common, polyostotic FD can occur in the context of McCune-Albright syndrome, a multisystem developmental disorder. Our patient, a 55-year-old female with a history of diabetes, hypothyroidism, and dyslipidemia, presented with progressively worsening dysphagia, sternal pain, and swelling over three years. Clinical examination revealed a tender and hard swelling in the upper sternal area, prompting further evaluation. Laboratory results, including bone turnover markers, were unremarkable. Imaging studies unveiled a sizable anterior mediastinal lesion with heterogeneous enhancement and coarse calcifications, initially raising concerns of malignancy. Subsequent positron emission tomography scan findings confirmed FD involvement in both the sternum and right femur. Histopathology of the mediastinal mass revealed a spindle cell neoplasm with bony metaplasia, consistent with FD, supported by immunohistochemistry. A multidisciplinary team affirmed the diagnosis of polyostotic FD, and follow-up imaging after one year demonstrated no significant change in lesion size, confirming a benign etiology. While bisphosphonate therapy was planned, regrettably, the patient was lost to follow-up. This case underscores the importance of a comprehensive, multidisciplinary approach in diagnosing and managing complex presentations of FD, ultimately contributing to improved patient care and outcomes in such instances.

Precocious Puberty: Types, Pathogenesis and Updated Management

Precocious puberty (PP) means the appearance of secondary sexual characters before the age of eight years in girls and nine years in boys. Puberty is indicated in girls by the enlargement of the breasts (thelarche) in girls and in boys by the enlargement of the testes in either volume or length (testicular volume = 4 mL, testicular length = 25 mm, or both). Two types of PP are recognized - namely central PP (CPP) and peripheral PP (PPP). This paper aims to describe the clinical findings and laboratory workup of PP and to illustrate the new trends in the management of precocious sexual maturation. Gonadotropin-releasing hormone (GnRH)-independent type (PPP) refers to the development of early pubertal maturation not related to the central activation of the hypothalamic-pituitary-gonadal (HPG) axis. It is classified into genetic or acquired disorders. The most common forms of congenital or genetic causes involve McCune-Albright syndrome (MAS), familial male-limited PP, and congenital adrenal hyperplasia. The acquired causes include exogenous exposure to androgens, functioning tumors or cysts, and the pseudo-PP of profound primary hypothyroidism. On the other hand, CPP is the most common and it is a gonadotropin-dependent form. It is due to premature maturation of the HPG axis. CPP may occur as genetic alterations, such as MKRN3, DLK1, or KISS1;as a part of mutations in the epigenetic factors that regulate the HPG axis, such as Lin28b and let-7; or as a part of syndromes, central lesions such as hypothalamic hamartoma, and others. A full, detailed history and physical examination should be taken. Furthermore, several investigations should be conducted for both types of PP, including the estimation of serum gonadotropins such as luteinizing and follicle-stimulating hormones and sex steroids, in addition to a radiographic workup and thyroid function tests. Treatment depends on the type of PP: Long-acting GnRHa, either intramuscularly or implanted, is the norm of care for CPP management, while in PPP, especially in congenital adrenal hyperplasia, the goal of management is to suppress adrenal androgen secretion by glucocorticoids. In addition, anastrozole and letrozole - third-generation aromatase inhibitors - are more potent for MAS.

A Rare Case of Headache in a Patient With McCune-Albright Syndrome: A Triple Threat

A 26-year-old male presented with facial asymmetry since 11 years of age and painless progressive diminution of vision in the left eye since 16 years of age. He presented with an exacerbation of headaches for the past two months. On examination, he was tall and had acral enlargement, craniofacial deformity, and bilateral asymmetric testicular enlargement. Investigations revealed high insulin-like growth factor 1, non-suppressible growth hormone on oral glucose tolerance tests, and multiple pituitary hormone deficiencies. MRI showed pituitary macroadenoma with craniofacial and sphenoid fibrous dysplasia as well as multiple tuberculomas. Cerebrospinal fluid testing showed high protein, low glucose, and high adenosine deaminase, all consistent with a diagnosis of central nervous system (CNS) tuberculosis. His headache did not respond significantly to either octreotide or zoledronic acid. The patient was then initiated on antitubercular therapy, which led to near-complete resolution of the headache and CNS lesions within three months of therapy. CNS tuberculosis was a masquerader in the index case of acrogigantism due to McCune-Albright syndrome. Headaches may be multifactorial in a given case of acromegaly, and investigating for alternative or additional causes especially when dealing with treatment-refractory cases can be rewarding.

Intramedullary Nailing for Lower Limb Polyostotic Fibrous Dysplasia in Children: A Long-term Follow-up Study

BACKGROUND

In children, intramedullary nailing (IN) has been proposed as the best treatment when the femur and tibia are totally affected by fibrous dysplasia (FD). However, in younger children IN must be repeated to maintain stabilization of the affected skeletal segment during growth. We report the long-term results in a cohort of patients in whom more than two-thirds of cases had IN repeated during growth.

METHODS

Twenty-nine femurs and 14 tibias totally affected by FD were treated by IN in 21 patients with polyostotic FD and McCune-Albright syndrome. Thirteen patients with 35 femoral and tibial deformities had a painful limp whereas 8 presented fractures. The patients had their first IN at a mean age of 9.26±2.68 years (range: 4 to 14 y). IN was repeated during growth in the younger patients, and all the patients underwent a mean of 2.13 femoral and 1.50 tibial IN per limb. The last IN was performed at a mean age of 16.42±1.95 years (range: 11 to 19 y). Titanium elastic nails and adult humeral nails were used in younger children, whereas adult femoral cervicodiaphyseal and interlocking tibial nails were used in older children and adolescents. At the latest follow-up, the patients were evaluated with a clinicoradiographic scale. All the data were statistically analyzed.

RESULTS

The mean length of follow-up from the last IN was 6.47±3.10 years (range: 3 to 14 y), and the mean age of the patients at follow-up was 22.85±3.53 years (range: 14 to 29 y) when lower limbs were fully grown in all but 1 patient. Satisfactory long-term results were obtained in about 81% of our patients, while complications occurred in 32.5% of the 43 cases.

CONCLUSION

Lower limb IN-that was repeated in younger children during growth-provided satisfactory long-term results in most of our patients, with fracture and deformity prevention and pain control, regardless of the high rate of complications that mainly affected the femoral cases. Missing scheduled follow-ups was the main predictor of a poor result.

LEVEL OF EVIDENCE

Level IV-case series.

Postoperative thyroid crisis in an 11-year old male with McCune-Albright syndrome and atypical triiodothyronine hyperthyroidism: A case report

RATIONALE

McCune-Albright syndrome (MAS) is a rare heterogeneous clinical disease caused by sporadic, somatic, and postzygotic mutations. Thyroid crisis is even rare in patients with MAS, and we report the clinical outcomes of the first case of a MAS patient with atypical triiodothyronine (T3) hyperthyroidism who developed thyroid crisis after orthopedic surgery.

PATIENT CONCERNS

The patient with MAS and atypical T3 hyperthyroidism was an 11-year-old man who had undergone surgery for a right femur fracture and shepherd bending deformity. His main symptoms were dizziness, nausea, and vomiting with elevated body temperature because of developed thyroid crisis. Thyroid function tests showed high T3 and remarkably high free T3 levels, and remarkably increased thyrotropin level, but unchanged thyroxine and free thyroxine levels.

DIAGNOSIS

The patient was diagnosed with postoperative thyroid crisis following surgery for a right femur fracture, shepherd bending deformity, and MAS with atypical T3 hyperthyroidism.

INTERVENTIONS

Propranolol was intravenously administered. The therapy included intravenous hydrocortisone, a saturated solution of potassium iodine and propylthiouracil, and continuous physical cooling.

OUTCOMES

The patient was discharged after achieving a stable condition with normal thyroid and liver function after surgery because of active anti-thyroid crisis treatment.

LESSONS

The operation of such patients should focus on the pre-operative heart rate, platelet level, and thyroid hormone levels. Abnormal values should be adjusted to the normal range, and such patients should achieve complete hemostasis and transfuse with blood following surgery anemia.

Pseudo-pheochromocytoma due to obstructive sleep apnea: a case report

SUMMARY

Obstructive sleep apnea (OSA) is a condition of intermittent nocturnal upper airway obstruction. OSA increases sympathetic drive which may result in clinical and biochemical features suggestive of pheochromocytoma. We present the case of a 65-year-old male with a 2.9-cm left adrenal incidentaloma on CT, hypertension, symptoms of headache, anxiety and diaphoresis, and persistently elevated 24-h urine norepinephrine (initially 818 nmol/day (89-470)) and normetanephrine (initially 11.2 µmol/day (0.6-2.7)). He was started on prazosin and underwent left adrenalectomy. Pathology revealed an adrenal corticoadenoma with no evidence of pheochromocytoma. Over the next 2 years, urine norepinephrine and normetanephrine remained significantly elevated with no MIBG avid disease. Years later, he was diagnosed with severe OSA and treated with continuous positive airway pressure. Urine testing done once OSA was well controlled revealed complete normalization of urine norepinephrine and normetanephrine with substantial symptom improvement. It was concluded that the patient never had a pheochromocytoma but rather an adrenal adenoma with biochemistry and symptoms suggestive of pheochromocytoma due to untreated severe OSA. Pseudo-pheochromocytoma is a rare presentation of OSA and should be considered on the differential of elevated urine catecholamines and metanephrines in the right clinical setting.

LEARNING POINTS

Obstructive sleep apnea (OSA) is a common condition among adults. OSA may rarely present as pseudo-pheochromocytoma with symptoms of pallor, palpitations, perspiration, headache, or anxiety. OSA should be considered on the differential of elevated urine catecholamines and metanephrines, especially in patients with negative metaiodobenzylguanidine (MIBG) scan results.

A Shepherd's Crook Deformity of Proximal Femur Treated by Valgus Osteotomy and Bone Grafting

The Shepherd’s crook deformity of the proximal femur is a characteristic radiologic feature of fibrous dysplasia. It may be limited to a single bone, which is called monostotic, or may be polyostotic involving multiple bones as seen in McCune-Albright Syndrome. We report a case of a 19-year-old male patient who presented to us with pain in the right hip for one year. He had dysmorphic facies and multiple café-au-lait spots over the back, which were suggestive of McCune-Albright Syndrome. The radiographs of the hip showed varus deformity of the proximal femur. A lateral closing wedge osteotomy was done and the defect was filled with morselised femoral head allografts and fibular strut allografts. At the 14-month follow-up, the patient remained functionally active without any symptoms. The use of morselised femoral head allograft combined with strut fibular allograft ensures both stability and improved biology at the site of the lesion without any donor site morbidity.

Fibrous dysplasia of the proximal femur: surgical management options and outcomes

PURPOSE

The management of proximal femoral deformity in fibrous dysplasia (FD) is a challenge to the orthopaedic surgeon. The purpose of this study was to analyze the various presentations of FD of proximal femur and the results of the various treatment modalities for the same.

METHODS

This is a retrospective cohort study of 23 patients (24 femora) with FD who underwent surgery for the proximal femur. The study sample included 14 males, nine females. Ten patients had a monostotic disease, eight patients had polyostotic disease, and five patients had McCune-Albright syndrome.

RESULTS

Group 1: shepherd crook deformity-included five patients who underwent femoral neck osteotomy. Four patients had intramedullary (IM) nailing with neck cross-pinning and all patients showed union. One patient was stabilized with external fixation, which failed. Group 2: nine patients (ten femora) presented with frank pathological fracture. Nine underwent fixation with IM nailing, one with locking plate and screws. Three patients had to undergo more than one procedure and all fractures showed good union. Group 3: nine patients who presented with bone cyst and pain. All patients underwent biopsy; four of them had curettage with bone graft.

CONCLUSION

Shepherd crook deformity can be treated by a well-planned osteotomy and fixation with intramedullary implants with neck cross-pinning. Frank pathological fractures fixation with an intramedullary nail has excellent results even if not accompanied by resolution of the fibrodysplastic lesion. More than one procedure may be required. External fixation is not an optimal choice for fixation of femoral osteotomies in FD.

McCune-Albright syndrome mimicking malignancy: an endocrine disease from oncologist's perspective

Fibrous dysplasia (FD) is categorized as either monostotic or polyostotic and may occur as a component of McCune-Albright syndrome (MAS). Imaging findings can mimic neoplastic diseases. We present a case of MAS initially suspected to have neoplastic disease. A 9-year-old girl was admitted to pediatric emergency with ataxia. Upon hospitalization, an extradural mass was seen on cranial magnetic resonance imaging (MRI) and the bone survey showed lytic lesions in the long bones. The patient was referred to the pediatric oncology department with a presumptive diagnosis of Langerhans cell histiocytosis or metastatic tumor. Further investigations demonstrated that the patient had MAS and coexisting postinfectious cerebellitis. The findings in this patient demonstrate that the radiographic findings and the clinical presentation of FD and MAS may be similar to those of malignant diseases.

Mechanism of FGF23 processing in fibrous dysplasia

Fibroblast growth factor-23 (FGF23) is a phosphate- and vitamin D-regulating hormone derived from osteoblasts/osteocytes that circulates in both active (intact, iFGF23) and inactive (C-terminal, cFGF23) forms. O-glycosylation by O-glycosyl transferase N-acetylgalactosaminyltransferase 3 (ppGalNAcT3) and differential cleavage by furin have been shown to be involved in regulating the ratio of active to inactive FGF23. Elevated iFGF23 levels are observed in a number of hypophosphatemic disorders, such as X-linked, autosomal recessive, and autosomal dominant hypophosphatemic rickets, whereas low iFGF23 levels are found in the hyperphosphatemic disorder familial tumoral calcinosis/hyperphosphatemic hyperostosis syndrome. Fibrous dysplasia of bone (FD) is associated with increased total FGF23 levels (cFGF23 + iFGF23); however, classic hypophosphatemic rickets is uncommon. Our results suggest that it can be explained by increased FGF23 cleavage leading to an increase in inactive cFGF23 relative to active iFGF23. Given the fact that FD is caused by activating mutations in the small G-protein G(s) α that results in increased cyclic adenosine monophosphate (cAMP) levels, we postulated that there may be altered FGF23 cleavage in FD and that the mechanism may involve alterations in cAMP levels and ppGalNacT3 and furin activities. Analysis of blood specimens from patients with FD confirmed that the elevated total FGF23 levels are the result of proportionally increased cFGF23 levels, consistent with less glycosylation and enhanced cleavage by furin. Analysis of primary cell lines of normal and mutation-harboring bone marrow stromal cells (BMSCs) from patients with FD demonstrated that BMSCs harboring the causative G(s) α mutation had higher cAMP levels, lower ppGalNAcT3, and higher furin activity. These data support the model wherein glycosylation by ppGalNAcT3 inhibits FGF23 cleavage by furin and suggest that FGF23 processing is a regulated process that controls overall FGF23 activity in FD patients.

Fibrous dysplasia & McCune-Albright syndrome: an experience from a tertiary care centre in north India

BACKGROUND & OBJECTIVES

Fibrous dysplasia (FD) is a rare metabolic bone disease and information available from India is limited to only anecdotal case reports. We describe the clinical profile and therapeutic outcome of 25 patients with FD observed over a period of 14 yr in a tertiary care centre from north India.

METHODS

In this retrospective study patients (n = 25) with diagnosis of fibrous dysplasia based on either classical radiological features and/or histological evidence on bone biopsy, were analyzed. Associated endocrinopathies if any, were evaluated. The diagnosis of McCune Albright syndrome (MAS) was considered when fibrous dysplasia was accompanied by either café-au-lait macules and/or endocrinopathies. The clinical presentation, biochemical parameters and imaging were analysed. Seven patients received bisphosphonate therapy. The final outcome and side effects were noted.

RESULTS

Age of the patients ranged from 7 to 48 yr (mean ± SD, 24.2 ± 11.4 yr) with a lag time between onset of symptoms and presentation ranging from 1 to 20 yr (mean ± SD, 6.6 ± 6.2 yr). The mean duration of follow up was 3.5 ± 2.1 yr. Eighteen (72%) patients had polyostotic disease while the remaining had monostotic FD. Eight patients had endocrinopathies: five had acromegaly, one each had gonadotropin independent precocious puberty (GIPP), hyperthyroidism and hypophosphatemic rickets. One child with GIPP later developed hyperthyroidism. McCune Albright syndrome was observed in 10 (40%) patients. A majority of the patients underwent various minor or major surgical procedures and seven patients received bisphosphonates for recurrent pathological fractures. Bone pain was reduced in all bisphosphonate treated patients with a decrease in subsequent fractures.

INTERPRETATION & CONCLUSIONS

This series of FD patients from north India shows the varying presentations of this rare disease. Medical treatment with bisphosphonates appears to be potentially rewarding.

Potent constitutive cyclic AMP-generating activity of XLαs implicates this imprinted GNAS product in the pathogenesis of McCune-Albright syndrome and fibrous dysplasia of bone

Patients with McCune-Albright syndrome (MAS), characterized primarily by hyperpigmented skin lesions, precocious puberty, and fibrous dyslasia of bone, carry postzygotic heterozygous mutations of GNAS causing constitutive cAMP signaling. GNAS encodes the α-subunit of the stimulatory G protein (Gsα), as well as a large variant (XLαs) derived from the paternal allele. The mutations causing MAS affect both GNAS products, but whether XLαs, like Gsα, can be involved in the pathogenesis remains unknown. Here, we investigated biopsy samples from four previously reported and eight new patients with MAS. Activating mutations of GNAS (Arg201 with respect to the amino acid sequence of Gsα) were present in all the previously reported and five of the new cases. The mutation was detected within the paternally expressed XLαs transcript in five and the maternally expressed NESP55 transcript in four cases. Tissues carrying paternal mutations appeared to have higher XLαs mRNA levels than maternal mutations. The human XLαs mutant analogous to Gsα-R201H (XLαs-R543H) showed markedly higher basal cAMP accumulation than wild-type XLαs in transfected cells. Wild-type XLαs demonstrated higher basal and isoproterenol-induced cAMP signaling than Gsα and co-purified with Gβ1γ2 in transduced cells. XLαs mRNA was measurable in mouse calvarial cells, with its level being significantly higher in undifferentiated cells than those expressing preosteoblastic markers osterix and alkaline phosphatase. XLαs mRNA was also expressed in murine bone marrow stromal cells and preosteoblastic MC3T3-E1 cells. Our findings are consistent with the possibility that constitutive XLαs activity adds to the molecular pathogenesis of MAS and fibrous dysplasia of bone.

Treatment of precocious puberty in McCune-Albright syndrome

McCune-Albright syndrome (MAS) is typically defined as a triad of precocious puberty (PP), café au lait spots and fibrous dysplasia of bone. PP is the most common endocrinological manifestation of this rare disease and is much more common in girls than in boys. The treatment options for PP associated with MAS have evolved over the last twenty plus years. Therapy in girls typically includes the use of an anti-estrogen, while treatment options in boys include an antiandrogen in combination with an aromatase inhibitor (AI). This article will briefly review the older therapies and explain why they have largely been supplanted by newer approaches. We will discuss current pharmacotherapy options for the treatment of PP in MAS and finally describe potential novel therapies that will hopefully enable optimal care for affected patients.

A case of McCune-Albright syndrome with associated multiple endocrinopathies

McCune-Albright syndrome (MAS) is a rare disorder that develops from an activating mutation in the Gs gene. It is characterized by an association with Polyostotic fibrous dysplasia, and precocious puberty, Caf-au-lait pigmentation, and other endocrinopathies that result from the hyperactivity of a variety of endocrine glands. Recently we encountered a patient with MAS with fibrous dysplasia, skin pigmentation, acromegaly, hyperprolactinemia and a thyroid nodule. A 23-year-old male presented for an evaluation of a change in his facial structures. Fibrous dysplasia was diagnosed by a bone biopsy and radiographic studies. The GH level increased paradoxically after an oral glucose load. The plasma prolactin, IGF-1 and alkaline phosphatase were high. Thyroid ultrasonography revealed multiple nodules. The brain MRI demonstrated a mass in the left pituitary gland. Genetic analysis identified a change from Arg (CGT) at codon 201 to Cys (TGT).