Biopsia del músculo recto lateral orbitario como diagnóstico de cáncer de mama metastásico no conocido / Lateral rectus muscle biopsy as diagnosis of unknown metastatic breast cancer

Mujer de 58 años sin antecedentes médicos de interés que consulta por diplopía binocular de una semana de evolución, asociada a dolor costal, disnea, astenia intensa y pérdida de peso de 2 meses de evolución. En la analítica de urgencia presenta hipercalcemia, insuficiencia renal y bicitopenia, y en la radiografía de tórax de urgencias se observan múltiples imágenes osteoclásticas que orientan inicialmente a mieloma múltiple con afectación extraósea. Además del estudio correspondiente, ante la diplopía horizontal se realiza TC craneal sin contraste, donde se observa una lesión adyacente a la pared lateral de la órbita izquierda, de densidad de partes blandas, que incluye el músculo recto externo y ejerce efecto masa sobre el nervio óptico desplazándolo medialmente. Además se observan múltiples lesiones líticas de distribución difusa en la calota, con patrón permeativo "en sal y pimienta". Se procede a la biopsia del músculo recto lateral y ósea de ala sacra, obteniendo como resultado metástasis de carcinoma compatible con origen mamario. Presentamos un caso atípico de diplopía horizontal en el contexto de una paciente con un cuadro constitucional severo sin diagnóstico establecido, en el que la biopsia del recto lateral, junto con la biopsia de médula ósea, son claves a la hora del diagnóstico de confirmación

The case concerns a 58 year-old female with no medical history of interest who consulted due to binocular diplopia of one week onset. It was associated with costal pain, dyspnoea, intense asthenia and weight loss of 2 months onset. In the blood analysis in the Emergency Department it showed hypercalcaemia, renal failure, and bicytopenia. The chest x-ray showed lytic bone lesions that initially lead to multiple myeloma with extra-osseous involvement. In addition to the corresponding study, in case of horizontal diplopia, a cranial CT scan without contrast was performed where an adjacent lesion to the lateral wall of the left orbit is observed. This was of soft tissue density, and included the external rectus muscle that exerts a mass effect on the optic nerve by displacing it medially. Many lytic bone diffuse lesions with salt and pepper pattern were found in the calotte. A rectus lateral muscle and bone biopsy of the sacral wing was performed, resulting in metastasis of carcinoma compatible with mammary origin. An atypical case is presented of horizontal diplopia in the context of a patient with a severe constitutional picture with no established diagnosis, in which the biopsy of the lateral rectum was key to the confirmation diagnosis

Lateral rectus muscle biopsy as diagnosis of unknown metastatic breast cancer. / Biopsia del músculo recto lateral orbitario como diagnóstico de cáncer de mama metastásico no conocido.

The case concerns a 58 year-old female with no medical history of interest who consulted due to binocular diplopia of one week onset. It was associated with costal pain, dyspnoea, intense asthenia and weight loss of 2 months onset. In the blood analysis in the Emergency Department it showed hypercalcaemia, renal failure, and bicytopenia. The chest x-ray showed lytic bone lesions that initially lead to multiple myeloma with extra-osseous involvement. In addition to the corresponding study, in case of horizontal diplopia, a cranial CT scan without contrast was performed where an adjacent lesion to the lateral wall of the left orbit is observed. This was of soft tissue density, and included the external rectus muscle that exerts a mass effect on the optic nerve by displacing it medially. Many lytic bone diffuse lesions with salt and pepper pattern were found in the calotte. A rectus lateral muscle and bone biopsy of the sacral wing was performed, resulting in metastasis of carcinoma compatible with mammary origin. An atypical case is presented of horizontal diplopia in the context of a patient with a severe constitutional picture with no established diagnosis, in which the biopsy of the lateral rectum was key to the confirmation diagnosis.