Hippocrates, Epidemics 5.101

 “A woman in Abdera developed cancer on her chest, and bloody plasma leaked out through her nipple. Once the flowing stopped, she died.”

Γυναικί, ἐν Ἀβδήροισι καρκίνωμα ἐγένετο περὶ στῆθος, διὰ τῆς θηλῆς ἔρρει ἰχὼρ ὕφαιμος· ἐπιληφθείσης δὲ τῆς ῥύσιος ἔθανεν.

There is an earlier account of breast cancer in Herodotus:

Herodotus, 3.133

“A little while later following these events, some other things happened. Cyrus’ daughter and Dareios’ wife, Atossa, developed a swelling in her breast. It burst out and expanded. As long as it was rather small, she hid it and told no one because she was ashamed. But when it became worse, she summoned Democedes and showed him. He told her that he could make her  healthy again but had her swear to him that she would reward him with whatever he asked from her, but that he would request nothing which would bring shame on her.”

ἐν χρόνῳ δὲ ὀλίγῳ μετὰ ταῦτα τάδε ἄλλα συνήνεικε γενέσθαι. Ἀτόσσῃ τῇ Κύρου μὲν θυγατρὶ Δαρείου δὲ γυναικὶ ἐπὶ τοῦ μαστοῦ ἔφυ φῦμα, μετὰ δὲ ἐκραγὲν ἐνέμετο πρόσω. ὅσον μὲν δὴ χρόνον ἦν ἔλασσον, ἣ δὲ κρύπτουσα καὶ αἰσχυνομένη ἔφραζε οὐδενί: ἐπείτε δὲ ἐν κακῷ ἦν, μετεπέμψατο τὸν Δημοκήδεα καί οἱ ἐπέδεξε. ὁ δὲ φὰς ὑγιέα ποιήσειν ἐξορκοῖ μιν ἦ μέν οἱ ἀντυπουργήσειν ἐκείνην τοῦτο τὸ ἂν αὐτῆς δεηθῇ: δεήσεσθαι δὲ οὐδενὸς τῶν ὅσα ἐς αἰσχύνην ἐστὶ φέροντα.

This has been called the “earliest account of inflammatory mastitis“

Hippocrates of Cos Epidemics 5.25

“In Larissa, Dyseris’ servant, when she was still young, experienced severe pain whenever she had intercourse. But she was without pain otherwise. She was never pregnant. When she was sixty, she started feeling pan at midday as if she were in severe labor pains. Before midday, she had eaten many leeks and when the pain overcame her and was the strongest of all, she rose up and felt something rough-edged near the entrance to her womb. Then, because she had already fainted, another woman inserted her hand and withdrew a stone which was as big as a spindle top and very rough. After that she was immediately healthy.”

Ἐν Λαρίσῃ ἀμφίπολος Δυσήριδος, νέη ἐοῦσα ὁκότε λαγνεύοιτο περιωδύνει ἰσχυρῶς, ἄλλως δὲ ἀνώδυνος ἦν. ἐκύησε δὲ οὐδέποτε. ἑξηκονταέτης γενομένη ὠδυνᾶτο ἀπὸ μέσου ἡμέρης, ὡς ὠδίνουσα ἰσχυρῶς· πρὸ δὲ μέσου ἡμέρης αὕτη πράσα τρώγουσα πολλά, ἐπειδὴ ὀδύνη αὐτὴν ἔλαβεν ἰσχυροτάτη τῶν πρόσθεν, ἀναστᾶσα ἐπέψαυσέ τινος τρηχέος ἐν τῷ στόματι τῆς μήτρης. ἔπειτα, ἤδη λειποψυχούσης αὐτῆς, ἑτέρη γυνὴ καθεῖσα τὴν χεῖρα ἐξεπίεσε λίθον ὅσον σπόνδυλον ἀτράκτου, τρηχύν· καὶ ὑγιὴς τότε αὐτίκα καὶ ἔπειτα ἦν.

5.50

“Nerios’ beautiful virgin daughter was twenty years old when she was struck on the forehead by a flat hand when she was playing with a young woman friend. When it happened, she became blind and out of breath; when she went home, a fever came over her right away. Her head hurt; she was flushed all over her face. By the seventh day, a bad-smelling pus flowed out of her right ear—it was red colored and there was more than a fifth of a cup of it. She seemed to feel better and was relieved. But she was stretched out again later because of a fever. She was feeling badly and was speechless. The right part of her face was contracted and she breathed with difficulty. She also had spasms of trembling. Her tongue stopped working. Her eye was affected. She died on the ninth day.”

Ἡ παρθένος ἡ καλὴ ἡ τοῦ Νερίου ἦν μὲν εἰκοσαέτης, ὑπὸ δὲ γυναίου φίλης παιζούσης πλατέῃ τῇ χειρὶ ἐπλήγη κατὰ τὸ βρέγμα. καὶ τότε μὲν ἐσκοτώθη καὶ ἄπνοος ἐγένετο, καὶ ὅτε ἐς οἶκον ἦλθεν αὐτίκα τὸ πῦρ εἶχε, καὶ ἤλγει τὴν κεφαλήν, καὶ ἔρευθος ἀμφὶ τὸ πρόσωπον ἦν. ἑβδόμῃ ἐούσῃ, ἀμφὶ τὸ οὖς τὸ δεξιὸν πύον ἐχώρησε δυσῶδες, ὑπέρυθρον, πλεῖον κυάθου, καὶ ἔδοξεν ἄμεινον ἔχειν, καὶ ἐκουφίσθη. πάλιν ἐπετείνετο τῷ πυρετῷ, καὶ κατεφέρετο, καὶ ἄναυδος ἦν, καὶ τοῦ προσώπου τὸ δεξιὸν μέρος εἵλκετο, καὶ δύσπνοος ἦν, καὶ σπασμὸς τρομώδης ἦν. καὶ γλῶσσα εἴχετο, ὀφθαλμὸς καταπλήξ· ἐνάτῃ ἔθανεν.