Rapidly growing fibro-osseous pseudotumor of the digits mimicking extraskeletal osteosarcoma

Fibro-Osseus Pseudotumor of the Digit: A Case Report and Review of Literature

Introduction

Bony subungual growths arising on the digital tip are uncommon. Among these, subungual exostosis is a common cause.

Case Presentation

We describe a 35-year-old-male patient with a rare occurrence of a fibro-osseus pseudotumor of the digit. It presents with reactive intramembranous ossification, with no continuity with the distal phalanx, helping differentiate it from a subungual exostosis. The patient presented with an asymptomatic subungual growth, lifting up the nail plate distally causing onycholysis. The characteristic clinical, radiological, and histopathological features of the case are described, which helped confirm the diagnosis.

Conclusion

Cases with fibro-osseus pseudotumor of the digit reported in literature are reviewed comprehensively. The factors helping differentiate this from the other bony tumors affecting the distal phalanx, including subungual exostosis, myositis ossificans, and osteosarcoma are also highlighted.

Fibro-Osseous Pseudotumor

Fibro-osseous pseudotumor is an extremely rare subcutaneous benign ossifying lesion associated with bone formation that is most commonly seen in the hands, followed by the toes. Because the tumor has a certain degree of invasiveness, it is often mistaken for malignancy, which leads to radical, excessive treatment. Our case involved a 32-year-old man with lesions on the left index finger. We documented the detailed data of diagnosis, treatment, and follow-up. We also conducted a review and summarized the published cases to advance our understanding of the disease, provide more accurate diagnostic criteria, and avoid inappropriate surgical procedures. [Orthopedics. 2021;44(6):e713-e718.].

Fibro-osseous Pseudotumor of the Distal Phalanx

Fibro-osseous pseudotumor of the digit is an unusual benign tumor that appears on the extremities. A 45-year-old, human immunodeficiency virus-positive man presented with a painful lesion on the tip of the fourth toe of his right foot. The tumor was completely excised without any connection to the underlying bone being observed, although the phalanx had to be extirpated. Histopathology confirmed the diagnosis of fibro-osseous pseudotumor. At the follow-up visit, 12 months later, no abnormalities were found.

Benign growing mass of the digit presenting as an ulcerated mass - case report and review of the literature

A 68 year-old female presents with an ulcerated mass of the 5th digit, with rapid growth during the previous month to surgery. The mass was excised and covered with a 4th dorsal metacarpal artery perforator flap. The histologic analysis was compatible with the diagnosis of fibro-osseous pseudotumor of the digit.

Ubiquitin-specific Peptidase 6 (USP6)-associated Fibroblastic/Myofibroblastic Tumors: Evolving Concepts

Ubiquitin-specific peptidase 6 (USP6) is a hominoid-specific gene residing on chromosome 17p13 and serves as a deubiquitinating enzyme with a diverse set of functions including intracellular trafficking, inflammatory signaling, cell transformation and protein turnover. USP6 rearrangements were first identified in aneurysmal bone cysts, resulting in promoter swapping and over-expression of wild type USP6. Several morphologically overlapping fibroblastic/myofibroblastic tumors are known to harbor USP6 rearrangements, including nodular fasciitis, cellular fibroma of tendon sheath, myositis ossificans and fibro-osseous pseudotumor of digits. Over the past few years, fusions involving the USP6 gene and various partner genes have been described in these neoplasms. The current World Health Organization Classification of Tumors of Soft Tissue suggests that USP6-rearranged lesions are typically benign and usually self-limited in their growth. This review provides an updated overview of the clinical, histological and molecular genetic features of USP6-associated fibroblastic/myofibroblastic tumors and discusses how these lesions should be best classified.

Florid reactive periostitis in the fifth phalange of a professional boxer: A case report

RATIONALE

Florid reactive periostitis is a rare, benign bone and chondrogenic lesion that develops most frequently in the phalanges of the hands. Although the definitive cause of florid reactive periostitis is unknown, the major inciting factor is generally considered to be trauma, including repetitive minor trauma.

PATIENT CONCERNS

We present a case of florid reactive periostitis affecting two contiguous phalangeal bones of the left fifth phalange of a 23-year-old male professional boxer. The patient had experienced chronic pain around the metacarpophalangeal joint of the left fifth phalange when punching with the left hand; this pain was improved but not resolved after conservative treatment.

INTERVENTIONS

Plain radiography of the fifth phalange revealed a bulging bone lesion on the volar side of the proximal phalanx and metacarpal of the left fifth phalange. Computed tomography also showed raised bony lesions on the volar side of these bones without bony destruction or intraregional calcification. Surgery was performed and histopathology revealed that the bone specimens comprised a mixture of fibrous connective tissue and relatively immature bone covered by bland osteoblasts.

DIAGNOSES

These findings were suggestive of a benign bone formation process, and the lesion was diagnosed as florid reactive periostitis.

OUTCOMES

The pain and tenderness in the left fifth phalange experienced during boxing had completely resolved by 6 months postoperatively, and 12 years postoperatively the patient had full range of motion and no recurrence of pain.

LESSONS

Traction force, such as those associated with "leading jabs," may induce repetitive minor trauma and subsequent periosteal damage, resulting in the gradual development of bulging bone ridges on the volar surface of the proximal fifth phalange and metacarpus of the hand.

Fibro-Osseous Pseudotumour of the Digit: An Illustrative Case and Review of the Literature

Fibro-osseous pseudotumour is a rare, benign ossifying tumour of soft tissue that should be considered in the differential diagnosis of any tumour affecting the digits. Clinical diagnosis is difficult and fibro-osseous pseudotumour is often mistaken for malignancy, leading to inappropriate treatment. Knowledge of its clinical and histopathological features thus allows for appropriate primary treatment, sparing the patient from unnecessary radical surgery associated with presumed malignancy. We present the case of a 48-year-old male with fibro-osseous pseudotumour affecting the right ring finger, successfully treated with local excision. This is the second reported Australian case of fibro-osseous pseudotumour, and we present an extensive review of the literature relating to the diagnosis and management of this rare tumour.

Fibro-osseous pseudotumor of the digit presenting as an ulcerated lesion: a case report

Fibro-osseous pseudotumor of the digit is rare benign lesion of subcutaneous tissue which is thought to be reactive process as a result of repeated trauma. We report a case of an ulcerated lesion of skin of middle finger, clinically thought to be leishmaniasis which after punch biopsy followed by excision turned out to be fibrosseous pseudotumor. Diagnosis of fibro-osseous pseudotumor requires immense precision as it can clinically mimic unungal exostosis and can sometimes be misinterpreted clinically and radiologically as myositis ossificans. We suggested an algorithimic approach for histopathologic assessment of fibro-osseous soft tissue lesions with evaluation of both stromal and osseous components. Bland fibroblastic stroma, mature osseous component with prominent osteoblastic rimming and absence of zonation pattern will support the diagnosis of fibro-osseous pseudotumor especially if located at a superficial and distal location.

Florid reactive periostitis of the metacarpal and phalanx: 2 case reports

Florid reactive periostitis is a rare benign fibro-osseous proliferative lesion of soft tissue and is mainly composed of fibrous connective tissue and mature bone. The lesion usually occurs in the finger and seldom in the metacarpal. The lesion mimics malignant and infectious disorders, thus often leading to inappropriate treatment. Radiography usually shows an ossified mass attached to the underlying hand bones without interruption of the cortex. We report 1 case of florid reactive periostitis with unossified mass and underlying bone marrow edema in the metacarpal of hand and 1 case with adjacent cortical destruction in the phalanx. In addition, we describe the imaging findings of computed tomography CT and magnetic resonance imaging MRI and discuss their diagnostic values compared with routine radiographic examination.

Acquired reactive digital fibroma: a clinicopathologic report of 5 cases of a new entity

BACKGROUND

Fibroblastic proliferations in the dermis comprise a heterogeneous group of disorders that can pose diagnostic challenges.

OBJECTIVE

We sought to study the clinicopathologic features of this tumor.

METHODS

We reviewed the clinicopathologic features of 5 unusual mesenchymal tumors of the digits that, to our knowledge, correspond to an entity not previously described.

RESULTS

The patients were 5 men. All cases were located in the digits and were associated with history of trauma. Histopathologically, the neoplasms were located mainly in the reticular dermis. The tumors consisted of solitary nodules composed of fascicles of benign-appearing spindle cells devoid of cytologic atypia. The spindle cells formed short fascicles arranged in a haphazard manner. On immunohistochemistry, the tumor cells expressed vimentin and in 2 cases, CD34. The tumor cells were negative for smooth muscle actin (SMA), desmin, h-caldesmon, epithelial membrane antigen (EMA), S100, CD68, CD99, and beta-catenin.

LIMITATIONS

Only 5 cases were studied.

CONCLUSIONS

Awareness of this entity is of importance to avoid misdiagnosis with other conditions. Based on the immunohistochemical pattern, we believe that these tumors are fibroblastic in origin. The peculiar gross appearance and location of the lesions is clinically quite distinctive and may lead to confusion with other neoplastic and reactive processes.

Acral angioosteoma cutis

Acral angioosteoma cutis is a benign lesion of unknown pathogenesis and is a newly described, distinct entity from other cutaneous lesions. It is clinically characterized by an exophytic lesion resembling pyogenic granuloma on the acral skin, combined with histologic findings of multiple tiny spicules composed of woven bone between well-formed capillaries proliferating in the superficial dermis. Here, we present a case of acral angioosteoma cutis on the left third toe of a 58-year-old woman, which was successfully treated by excision.

Fibro-osseous pseudotumor of the digit: a clinicopathological study of 17 cases

Fibro-osseous pseudotumor (FP) of the digit is a rare, non-neoplastic heterotopic ossifying lesion involving the subcutaneous tissues of the digits. To date, there are only a few published series in the literature. Our study of 17 cases, retrieved from the authors' referral archives, shows that the condition chiefly affects young to middle-aged adults (median = 34 years), with a slight female predominance and involves the fingers (n = 8) and toes (n = 8). One identical lesion was identified on the forehead (n = 1). Lesional size ranges from 0.8 to 5.6 cm. Treatment was by surgical excision. Histologically, 14 cases show a fairly well-circumscribed dermal (n = 10) or dermal and subcutaneous (n = 7) lesion with surface ulceration (n = 7). The lesion is composed of fascicles of variably cellular, spindle-shaped cells [calponin (n = 14) and smooth muscle actin (SMA) (n = 11) positivity], with minimal to mild atypia (n = 5), dispersed in a myxoid stroma, focally reminiscent of nodular fasciitis. At least focal irregular trabeculae with osteoid formation and osteoblastic rimming are seen in all cases. The main differential diagnosis is an extraskeletal osteosarcoma; however, this afflicts an older age group, with prominent cytological atypia and atypical mitoses. Clinical follow-up (range: 18 months - 14 years, n = 12) reveals evidence of local recurrence in some cases (n = 2), but no evidence of metastases. In conclusion, we report an additional 17 cases of this rare lesion to increase awareness amongst dermatopathologists.

Fibro-osseous pseudotumor of the thenar eminence: a rare aggressive but benign tumor

Fibro-osseous pseudotumor is a rare benign lesion that is characterized by fibroblastic proliferation with foci of osseous differentiation. The tumor commonly involves the digits and is usually mistaken for malignancy because of its aggressive nature thus resulting in surgical over treatment. We report a patient with fibro-osseous pseudotumor that involved the thenar eminence and was managed successfully by local resection from the surrounding structures with no residual loss of function.

Fibro-osseous pseudotumor of the digits: a rare tumor in an unusual location

Fibro-osseous pseudotumor of the digits (FOPT) is a rare benign lesion of the hand. When FOPT originates in an unusual anatomic region (other than the digits), it can imitate a malignant neoplasm, and consequently surgical treatment can be improper. This report describes a case of FOPT that developed in an unusual anatomic region: the first dorsal-extensor compartment of the wrist.