# High-grade Pleomorphic Sarcoma Associated with Metallosis in a Patient with Total Hip Arthroplasty

## TL;DR

A rare case of high-grade sarcoma linked to metallosis in a patient with a long-standing hip implant is reported, highlighting the need for vigilance in similar cases.

## Contribution

This case report presents one of the longest latency periods between hip arthroplasty and sarcoma diagnosis.

## Key findings

- A 24-year latency period between primary hip arthroplasty and sarcoma diagnosis was observed.
- The sarcoma was associated with metallosis and extensive tissue necrosis near the implant.
- The patient developed pulmonary metastases and died six months after diagnosis.

## Abstract

Although the relationship between hip arthroplasty and the development of sarcoma was first described in the literature about forty years ago, this association is extremely rare. In the present case report, we describe the association between orthopedic implants and soft tissue sarcoma in a 79-year-old man who underwent primary total hip arthroplasty (THA) for coxarthrosis 24 years ago. In the present case report, we describe the clinical evolution and the radiographic and histopathological findings of the lesion. In the intraoperative period of the second revision surgery, loosening of the acetabular and femoral components in association with extensive areas of necrosis and metallosis was evidenced. We performed debridement of the hip and right thigh region and removed the implants. Due to the extent of the lesion and to necrosis, it was not possible to perform a new joint reconstruction. The histopathological diagnosis of high-grade undifferentiated pleomorphic sarcoma associated with extensive areas of metallosis was confirmed in tissue adjacent to the implant. The patient developed pulmonary metastases and died 6 months after the diagnosis. Despite the rarity of this association, sarcomas should be considered in the differential diagnosis of aseptic loosening, especially in the presence of metallosis in the peri-implant tissue. To our knowledge, the 24-year latency period between primary THA and the establishment of a sarcoma diagnosis is one of the longest reported to date.

Apesar da relação entre artroplastia de quadril e o desenvolvimento de sarcoma ter sido descrita pela primeira vez na literatura há cerca de quarenta anos, esta associação é extremamente rara. No presente relato de caso, descrevemos a associação entre implante ortopédico e sarcoma de partes moles em um homem de 79 anos submetido a artroplastia primária total do quadril (ATQ) por coxartrose há 24 anos. Foram descritas a evolução clínica e os achados radiográficos e histopatológicos da lesão. No intraoperatório da segunda cirurgia de revisão, foi evidenciada soltura dos componentes acetabular e femoral em associação com extensas áreas de necrose e de metalose. Foi realizado desbridamento da região do quadril e da coxa direita e retirada dos implantes. Devido à extensão da lesão e da necrose, não foi possível realizar nova reconstrução articular. O diagnóstico histopatológico de sarcoma pleomórfico indiferenciado de alto grau associado a extensas áreas de metalose foi estabelecido no tecido adjacente ao implante. O paciente evoluiu com metástases pulmonares e faleceu 6 meses após o diagnóstico. Apesar da raridade da associação, os sarcomas devem ser considerados no diagnóstico diferencial das solturas assépticas, particularmente na presença de metalose no tecido peri-implantar. Pelo nosso conhecimento o período de latência de 24 anos entre a ATQ primária e o estabelecimento do diagnóstico de sarcoma é um dos mais longos relatado até o momento.