Preziosissimo Sangue di Nostro Signore Gesù Cristo ad Appio Latino is a 20th century convent church at Via Beata Maria De Mattias 10. This is by the Largo Pannonia in the Appio Latino quarter, just off the Via Gallia near the Porta Metronia. Pictures of the church at Wikimedia Commons are here.
The dedication is to the Precious Blood of Jesus Christ.
This is the convent church of the Generalate of the Congregation of Sisters, Adorers of the Precious Blood. It was built from 1940 to 1943, and looks like a design by Tullio Rossi in his typical neo-Romanesque style. However, the architect is given by info.roma as "Leonori". This cannot be Aristide Leonori, who died in 1928.
The edifice is in puce-coloured brick, with a nave having side aisles and a rectangular apse. There are two little semi-circular side chapels off each aisle.
The blank gabled façade is false, as the pitch of the nave roofline is continued to conceal the aisles. There is an external porch with three entrance arches rendered in white, these arches having no decoration or imposts. Above the porch is a round window with mullions in the form of a Greek cross. There is no other decoration, just bare brick walling.
The interior is in unplastered brick, with an unpainted coffered wooden ceiling. The nave arcade piers are square with chamfers, and odd-looking capitals formed from four rhomboidal stones each giving the effect of a crown.
The otherwise blank wall above the altar is dominated by a large mosaic of the Crucifixion in an Impressionistic style reminiscent of Picasso. This is by Augusto Ranocchi (1931-2011).
The stained glass in the nave windows representing the Instruments of the Passion is by Nocchi.
In one of the chapels is enshrined St Mary de Mattias, the foundress of the congregation. She was canonized in 2003.